Synthesis and evaluation as NOP ligands of some spiro[piperidine-4, 2′(1′H)-quinazolin]-4′(3′H)-ones and spiro[piperidine-4,5′(6′H)-[1,2,4]triazolo[1,5-c]quinazolines]

Article abstract of DOI:10.1248/cpb.54.611

Some spiro[piperidine-4,2′(1′H)-quinazolin]-4′(3′H) -ones 3 and spiro[piperidine-4,5′(6′H)-[1,2,4]triazolo-1,5-c] quinazolines] 4 were synthesized and evaluated as ligands of the nociceptin receptor. The examined compounds showed partial agonistic activity, except compounds 3, 4n that proved to be pure antagonists.

Full text of DOI:10.1248/cpb.54.611

May 2006
Chem. Pharm. Bull. 54(5) 611—622 (2006)
611
Synthesis and Evaluation as NOP Ligands of Some Spiro[piperidine-
4,2ꢀ(1ꢀH)-quinazolin]-4ꢀ(3ꢀH)-ones and Spiro[piperidine-4,5ꢀ(6ꢀH)-
[1,2,4]triazolo[1,5-c]quinazolines]
Carlo MUSTAZZA,* Anna BORIONI, Isabella SESTILI, Maria SBRACCIA, Andrea RODOMONTE,
Rosella FERRETTI, and Maria Rosaria DEL GIUDICE
Dipartimento del Farmaco, Istituto Superiore di Sanità; Viale Regina Elena 299, 00161 Roma, Italy.
Received October 20, 2005; accepted February 7, 2006
Some spiro[piperidine-4,2ꢀ(1ꢀH)-quinazolin]-4ꢀ(3ꢀH)-ones 3 and spiro[piperidine-4,5ꢀ(6ꢀH)-[1,2,4]triazolo-
[1,5-c]quinazolines] 4 were synthesized and evaluated as ligands of the nociceptin receptor. The examined com-
pounds showed partial agonistic activity, except compounds 3, 4n that proved to be pure antagonists.
Key words spiropiperidine; spiropiperidine triazoloquinazoline; nociceptin receptor ligand; opioid
The nociceptin (NOP) receptor is the latest identified size a series of new spiropiperidine-quinazolinones 3 and
member of the transmembrane G-protein coupled receptors spiropiperidine-triazoloquinazolines 4 whose structure partly
family comprising d, k and m opioid receptors.1)
recalled some very potent agonists by Roche16) (Fig. 1). Our
Its original homology cloning and the isolation from brain aim was to explore the influence of the following structural
extracts of the endogenous ligand, the heptadecapeptide noci- features on affinity and selectivity:
ceptin (NC),2,3) gave rise to a great interest in clarifying its • the presence of a fused benzene ring instead of the typical
physiological functions. The receptor, distributed in both
N-phenyl substituent
central and peripheral nervous systems and in non-neuronal • the inversion of the NH–CO sequence respect to the lead
tissues, revealed to be involved in several processes including molecules
modulation of nociception,2,3) locomotor activity,3) reversal of • the different length and branching of the alkylsubstituent
stress-induced analgesia,4) modulation of learning and mem-
on the cyclohexane ring
ory,5—7) regulation of neurotransmitter and hormone re- • the substitution of the amidic moiety by a fused triazole
lease,8,9) neuronal differentiation.10,11)
ring.
In the last years NOP receptor has become an important
biological target for a number of potential therapeutic appli- Results and Discussion
cations associated with pain, stress and anxiety, cognitive de-
Chemistry The synthetical pathway to the target com-
ficiency, eating and other disorders.12) At the same time, con- pounds is outlined in Fig. 2.
sistent advances have been attained in the design and discov-
ery of new ligands, and many nonpeptide small molecules
were developed as agonists or antagonists.13—17)
The 1-substituted piperidones 2 were obtained by reaction
Among several scaffolds, spiropiperidines showed to be an
interesting and promising class of NOP ligands. They are
structurally related to lofentanyl (Fig. 1), a m-selective opiate
ligand having also affinity for the NOP receptor.
The NOP active site18,19) was first investigated by computa-
tional studies on its complex with nociceptin20,21) and lofen-
tanyl.21) Anyway spiropiperidines22) were useful tools for the
elucidation of the mechanism of interaction of small non
peptidic molecules. These studies indicated the electrostatic
interaction of protonated piperidinic nitrogen with Asp130
and a hydrogen bond between the small molecule and Thr305
as determinant features for affinity.
Most of the spiropiperidines have been reported to possess
high agonistic activity and selectivity as Ro 64-619814) (Fig.
1) which also exhibited anxiolytic properties.
The interest in this scaffold of compounds also relies in
their capability of reversing their biological effect after small
structural modifications. Some antagonists developed by
Banyu15) (Fig. 1) that differ from their “isomer” Ro 64-6198
in the imidazolinone amidic sequence, can be mentioned as
an example.
The intriguing and often complex structure–activity rela-
Fig. 1. Structures of NOP Receptor Ligands and of the Synthesized Com-
tionships of spiropiperidinic NOP ligands led us to synthe- pounds
∗ To whom correspondence should be addressed. e-mail: mustazza@iss.it
© 2006 Pharmaceutical Society of Japan

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Vol. 54, No. 5
of the 1-ethyl-1-methyl-4-oxopiperidinium iodide 123) with
the corresponding amines in a hydroalcoholic medium in the
presence of sodium carbonate at reflux. The reaction of 1
with 4-alkylcyclohexylamines used as isomeric mixtures,24)
gave the expected cis and trans isomers which were sepa-
rated by column chromatography on aluminium oxide or sil-
ica gel by eluting with ethyl acetate/hexane mixtures. The as-
1
signment of their configuration was performed by H-NMR
in pyridine-d5 solution. The cis isomer always eluted first.
Compounds 2 were allowed to react with anthranylamides
in an acetic acid–sulfuric acid mixture to give spiro com-
pounds 3. Reaction of 2 with 2-([1,2,4]triazol-3-yl)aniline25)
in the same acidic medium gave the [1,5-c] fused compounds
4.
N6ꢀ-Methylation of compounds 4d cis and 4e cis was
achieved by reaction with formic acid and sodium borohy-
dride to give 4m cis and 4n cis respectively.
In order to obtain an experimental evidence that we had
[1,5-c] and not [4,3-c] ring fusion, we synthesized the 5,6-di-
hydro-[1,2,4]triazolo[1,5-c]quinazoline by reduction of the
[1,2,4]triazolo[1,5-c]quinazoline25) with sodium borohydride
1
and observed that its H-2 signal in the H-NMR spectrum in
DMSO-d6 had the same position (dꢁ8.04 ppm) of the corre-
sponding H-2ꢀ protons in compounds 4.
Pharmacology The binding affinities of the synthesized
compounds were measured by employing [125I]-nociceptin as
radiotracer. The most active compounds were also tested on
d, k and m receptors to estimate their selectivity towards all
the opioid receptor subtypes. In such experiments we used
[3H]-naltrindole for d, and [3H]-diprenorphine for k and m as
radioligands. The results are shown in Tables 1 and 2.
The biological efficacy of the compounds was evaluated as
their ability to enhance the binding of [35S]GTPgS in the
presence of GDP, using membranes isolated from cells trans-
fected with NOP receptors. This assay, based on GTP/GDP
exchange on the G protein a subunit, is a direct measure of
receptor-mediated G protein activation (Fig. 3). The mem-
branes were prepared from a cell line expressing a tandem
fusion protein between the NOP receptor and the a subunit
of Go. As previously reported26) the forced 1 : 1 stoichiometry
of expression of receptor and Ga subunit in such system
greatly enhances the GTPgS response and allows to detect
even small levels of ligand efficacy.
Fig. 2. Synthetical Route to Compounds 3 and 4
Moreover, for the cis compounds 3d, e, m, n, s, t and compared to linear methyl, ethyl and propyl substituents
4d, e, m, n we scanned the [35S]GTPgS binding response at a (3a—c, 4a—c).
wide range of GDP concentrations in order to reveal the full
In both series 3 and 4 the cis conformers showed a higher
or partial agonism and the antagonism, of these compounds affinity than their trans isomers. This configurational effect
(Fig. 4). resulted more evident in the iso-propyl derivatives 3d, m,
The cis compounds 3m, 3n, 4m and 4n were also tested whose cis isomers were about 20 folds more active than their
for their potency to affect nociceptin-stimulated GTPgS corresponding trans.
binding. The dose-response curves are reported in Fig. 5.
Methylation or benzylation on the quinazolinone N1
Binding Affinity for NOP Receptor The most active tended not to affect the affinity of the ligands while N1-ben-
compounds (IC50 values ꢂ10 mM) are reported in Table 1. zylation of the less active compounds 3d trans and 3f, led to
The compounds 3f, g, i and their N1-methylated analogues a 10-fold increased affinity (3f IC50ꢁ50.8 mM, 3u IC50ꢁ
3o, p, r, bearing the aromatic substituent benzyl, phenethyl 5.1 mM).
and dibenzosuberyl on the piperidine nitrogen atom, showed
low affinity and have not been taken into account in the se- the isosteric triazole ring, to give compounds 4, resulted in a
lectivity and intrinsic activity experiments. general increase of potency mainly for the N-methyl and N-
The binding data of 4-alkylcyclohexyl derivatives indi- ethylcyclohexyl compounds 3a, b.
The substitution of the amide function HN3–C4ꢁO with
cated that branched alkyl groups, iso-propyl for 3d, m, s and
In conclusion, the binding studies suggest two essential
4d, m and tert-butyl for 3e, n, t and 4e, n, enhanced potency structural requirements for the affinity: a bent molecular

May 2006
613
Table 1. In Vitro Affinity of Compounds 3 and 4
IC50 (mM)
R
R1
Compound
NOP
m
d
k
4-Ethylcyclohexyl
4-Propylcyclohexyl
4-i-Propylcyclohexyl
4-i-Propylcyclohexyl
4-t-Butylcyclohexyl
4-t-Butylcyclohexyl
Adamantyl
4-Ethylcyclohexyl
4-Propylcyclohexyl
4-i-Propylcyclohexyl
4-i-Propylcyclohexyl
4-t-Butylcyclohexyl
4-t-Butylcyclohexyl
Adamantyl
4-i-Propylcyclohexyl
4-i-Propylcyclohexyl
4-t-Butylcyclohexyl
4-t-Butylcyclohexyl
Benzyl
4-Methylcyclohexyl
4-Methylcyclohexyl
4-Ethylcyclohexyl
4-Ethylcyclohexyl
4-Propylcyclohexyl
4-i-Propylcyclohexyl
4-i-Propylcyclohexyl
4-t-Butylcyclohexyl
4-t-Butylcyclohexyl
Adamantyl
H
H
H
H
H
3b cis
3c cis
3d cis
3d trans
3e cis
3e trans
3h
3k cis
3l cis
3m cis
3m trans
3n cis
3n trans
3q
3s cis
3s trans
3t cis
4.2ꢃ0.5
4.9ꢃ0.8
0.6ꢃ0.2
10.7ꢃ2.2
0.9ꢃ0.1
4.9ꢃ1.4
1.7ꢃ0.3
4.8ꢃ0.9
4.8ꢃ1.2
0.6ꢃ0.3
13.5ꢃ3.5
0.50ꢃ0.02
3.9ꢃ0.6
7.3ꢃ1.4
0.5ꢃ0.2
1.8ꢃ0.2
1.1ꢃ0.5
3.2ꢃ0.5
5.1ꢃ0.9
4.0ꢃ0.5
10.0ꢃ0.6
1.6ꢃ0.7
3.8ꢃ1.2
5.2ꢃ0.1
0.5ꢃ0.1
2.5ꢃ0.6
0.50ꢃ0.06
3.9ꢃ0.1
1.2ꢃ0.1
4.1ꢃ0.9
1.3ꢃ0.3
—
—
118ꢃ6
—
36.7ꢃ4.9
—
ꢄ1000
—
—
8.0ꢃ0.6
—
43.6ꢃ3.0
—
105ꢃ9
3.6ꢃ0.2
—
1.0ꢃ0.5
—
—
ꢄ100
—
ꢄ100
—
—
18.6ꢃ1.5
—
7.8ꢃ1.4
—
45.6ꢃ3.5
82.8ꢃ3.0
12.5ꢃ1.9
—
—
ꢄ1000
—
ꢄ1000
—
ꢄ1000
—
—
ꢄ1000
—
ꢄ1000
—
ꢄ1000
ꢄ1000
—
ꢄ1000
—
—
ꢄ1000
—
ꢄ1000
—
—
ꢄ1000
—
ꢄ1000
—
ꢄ1000
ꢄ1000
ꢄ1000
—
—
49.2ꢃ1.9
—
10.3ꢃ1.2
—
ꢄ1000
—
—
35.8ꢃ1.5
—
12.1ꢃ1.1
—
21.6ꢃ2.6
3.1ꢃ0.2
—
2.9ꢃ0.2
—
—
46ꢃ4.9
—
41ꢃ4.5
—
—
12.1ꢃ1.9
—
5.1ꢃ0.9
—
14.4ꢃ2.3
16.7ꢃ2.4
3.6ꢃ1.1
H
H
Methyl
Methyl
Methyl
Methyl
Methyl
Methyl
Methyl
Benzyl
Benzyl
Benzyl
Benzyl
Benzyl
H
H
H
H
H
H
H
H
H
3t trans
3u
4a cis
4a trans
4b cis
4b trans
4c cis
4d cis
4d trans
4e cis
4e trans
4h
4m cis
4n cis
H
Methyl
Methyl
4-i-Propylcyclohexyl
4-t-Butylcyclohexyl
Radioligands: [125I]-nociceptin for NOP, [3H]-naltrindole for d and [3H]-diprenorphine for k and m receptors. Data are given as meanꢃS.D. (nꢁ3).
Table 2. Selectivity towards d, k and m Receptors of cis iso-Propyl-, tert-
Butylcyclohexyl and Adamantyl Derivatives 3 and 4
Compound
da)
kb)
mc)
3d cis
3e cis
3h
3m cis
3n cis
3q
3s cis
3t cis
4d cis
4e cis
4h
ꢄ100
ꢄ100
ꢄ100
ꢄ100
ꢄ100
ꢄ100
ꢄ100
ꢄ100
ꢄ100
ꢄ100
ꢄ100
ꢄ100
ꢄ100
82
11
ꢄ100
57
ꢄ100
40
ꢄ100
14
ꢄ100
16
23
3
7
3
46
11
12
2.5
7
1
37
17
39
19
10
Fig. 3. Effect of Compounds 3 and 4 on G Protein a-Subunit Activation
4m cis
4n cis
The binding of [35S]GTPgS was measured in the presence of 300 nM GDP as de-
scribed in Experimental using membranes prepared from cells transfected with NOP
receptors. All compounds were present at a concentration of 100 mM. Data are
expressed as Bound/Total ratio of the radioligand (0.1 nM) and values are the meanꢃ
S.D. (nꢁ3).
3
a) Selectivity expressed as d IC50/NOP IC50 ratio. b) Selectivity expressed as
k IC50/NOP IC50 ratio. c) Selectivity expressed as m IC50/NOP IC50 ratio.
shape, derived from the cis 1,4-disubstitution of cyclohexane tion represented by N1-methyl or benzyl substituents did not
ring (Fig. 6) and a branched hydrophobic tail as iso-propyl or appear a strict requirement for affinity.
tert-butyl group. A lipophilic probe in the quinazolinone por-
Selectivity towards d, k and m Receptors The most ac-

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Fig. 4. Effects of the cis Compounds 3d, e, m, n, s, t and 4d, e, m, n on GPTgS Binding in Comparison with the Agonist Ro 64-6198
The binding of [35S]GTPgS was measured at increasing GDP concentrations as indicated on x-axis, in the absence (BAS) or in the presence of the ligands. Compounds 3n cis
and 4n cis exhibit lack of stimulation at all concentrations of GDP.
showed no affinity for the d and a moderate to good selectiv-
ity towards the m subtype, whereas the k subtype selectivity
ratio resulted lower. Adamantyl substituted 3h was the most
selective compound showing a selectivity ratio higher than
100 for d, k and m receptors.
These quinazolinone and triazoloquinazoline spiroderiva-
tives tended to possess higher k vs. m affinity compared to
analogue spiropiperidines bearing a N-phenylimidazolinone
ring.16) These results confirm the hypothesis that the hetero-
cyclic portion may be mainly responsible for selectivity in
these structures.27) The tetrahydroquinazoline moiety featur-
ing compounds 3 and 4, seems to be more suitable for inter-
action with the k receptor.
Biological Efficacy The biological efficacy of com-
pounds 3 and 4 expressed as ability to enhance the binding of
[35S]GTPgS in the presence of GDP, in membranes from
cells transfected with NOP receptors, is reported in Fig. 3.
This assay is a direct measure of the receptor-mediated G-
protein activation.
The examined compounds showed a variable partial ago-
nistic activity that gradually decreased to pure antagonism in
tert-butyl N1-methyl derivatives 3n cis and 4n cis. The results
reported in the histogram (Fig. 3) evidenced that the higher
efficacy was related to the presence of the iso-propyl sub-
Fig. 5. Antagonism of Nociceptin-Mediated Activation of Gao Induced by
stituent. Other structural features, as cis or trans configura-
tion, seemed not to be directly related to the biological effect,
although the highest activities both as regards partial ago-
nism and antagonism were associated to compounds in the
cis configuration (3d cis, 3e cis, 3s cis, 4d cis, 4m cis, 3n cis
and 4n cis).
A study at several GDP concentrations confirmed the par-
tially agonistic character of all compounds and the antago-
nism of 3n cis and 4n cis.
Compounds 3n cis and 4n cis
Concentration–response curves for nociceptin-mediated stimulation of [35S]GTPgS
in the presence of 300 nM GDP were performed in membranes expressing the ORL1R-
Gao fusion protein as described in Experimental. Curves were generated in the absence
and presence of increasing concentrations of either 3n cis (A) or 4n cis (B), as indi-
cated. Data points, after subtraction of basal activity (specific binding measured in the
absence of nociceptin) were plotted as fractional effect by dividing all values for the net
cpm stimulated by 10 mM nociceptin in the control curve of each experiment. Data were
analysed using ALLFIT (see Experimental), to compute the EC50 in the absence and
presence of the various concentrations of antagonist. Insets: Schild analysis of the data.
The log of the shift induced by each agonist (i.e. ratio of EC50 in the presence vs. ab-
sence of antagonist minus one, S-1) is plotted as a function of the log of the antagonist
concentration. Linear regression analysis of the data gave the following results (ꢃstan-
dard error): (A) slope 0.82ꢃ0.06, x value at yꢁ0 (pA2), 5.71ꢃ0.38; (B) slope
0.89ꢃ0.06, x value at yꢁ0 (pA2), 5.71ꢃ0.38.
In Fig. 4 the dose–response curves for the cis compounds
3d, 3e, 3m, 3n, 3s, 3t, 4d, 4e, 4m and 4n are reported as an
example.
To analyze the mechanism of antagonism exerted by com-
tive compounds 3 and 4 were tested for selectivity on the opi- pounds 3n cis and 4n cis we performed a classical Schild
oid d, k and m receptors (Tables 1, 2). In general compounds analysis.28) We measured the effects of increasing concentra-
3 tended to be more selective than triazoles 4. They all tions of the antagonist on the concentration–response curves

May 2006
615
of nociceptin. Both compounds induced a rightward shift of
the nociceptin-stimulated binding of [35S]GTPgS without
changing the maximum agonist stimulation (Fig. 5). The
corresponding Ki determined by the Schild plots, was
1.2ꢅ10ꢆ7 M (3n cis) and 3.7ꢅ10ꢆ7 M (4n cis), in good agree-
ment with binding results. The slope of the Schild plot
(0.82ꢃ0.06, 0.89ꢃ0.06 respectively) indicated both com-
pounds as competitive antagonists.
Molecular Modeling Studies To get a deeper insight
into the molecular bases of the interaction between NOP re-
ceptor and the synthesized compounds, molecular modeling
techniques were employed.
All the calculations were conducted on a Silicon Graphic
Octane R10000 workstation, within the Sybyl 6.91 software
package (Tripos, Inc. St. Louis, MO, U.S.A.).
The partial agonists N1-H 3d cis, 3e cis, 4d cis and 4e cis
and their N1-methyl derivatives 3m cis, 3n cis, 4m cis and
4n cis were taken into account. The pure agonist Ro 64-
619814) and the pure antagonist Banyu15) were also investi-
gated as a comparison.
The most stable molecular conformation was determined
by a simulated annealing protocol (10 cycles, heating the
system up to 2000 K in 1000 fs, annealing subsequently to
0 K in 2000 fs) followed by a geometrical optimization
(through the semi-empirical molecular orbital approach pro-
vided by the MOPAC 200029) program package) and a sys-
tematic search on the single bond between the piperidine and
Fig. 6. Configurations cis and trans of the Compounds 3e and 3n De-
picted in Their Lowest Energy Conformation
The structures were generated assuming the molecules to be mono-protonated under
physiological conditions.
(A)
A1
A2
(B)
B1
B2
Fig. 7. (A) The Ligand-NOP Receptor Complex is Depicted
A1: Compound 3e cis inserted in the binding pocket. A2: A side view of the NOP receptor, the bottom of the figure represents the intracellular side.
(B) The Final Results of the Two Docking Attempts are Depicted
Intermolecular interactions are represented by dashed lines. B1: In the first docking attempt ligand 3e cis points the carbonyl function toward Thr305. B2: In the second docking
attempt ligand 3e cis points the N1–H group toward Thr305.

616
Vol. 54, No. 5
the R substituent (30° steps). The structures were generated Conclusions
assuming that the molecules were protonated on the piperi-
dine nitrogen.
We have synthesized a series of new spiro[piperidine-
4,2ꢀ(1ꢀH)-quinazolin]-4ꢀ(3ꢀH)-ones and of spiro[piperidine-
Subsequently each ligand was manually docked into the 4,5ꢀ(6ꢀH)-[1,2,4]triazolo[1,5-c]quinazolines] that displayed
binding site of the NOP receptor22) in the middle of the trans- moderate to good affinity for the NOP receptors and behaved
membranes (TM) 3, 5, 6 and 7 at the head of the receptor as partial agonists.
(Fig. 7A) and between two pockets: the first one formed by
The peculiarity of this scaffold of ligands is that the sub-
Leu104, Gly108, Val126, Ile127, Ile198, Glu199, Cys200, stituent on the N1-position of the piperidine ring affected the
Leu201, Leu301, Tyr309 and the second one formed by affinity and modulated the efficacy. Moreover the presence of
Tyr131, Met134, Phe135, Ile204, Phe215, Phe220, Phe224, a methyl substituent on the quinazoline N1 joined to the pres-
Trp276, Val279, Val283. The Asp130 was chosen as an an- ence of a tert-butylcyclohexyl tail led to a loss of the intrin-
choring residue, as suggested by Tophan et al.30)
sic activity.
Energy minimisation followed the docking, therefore the
Molecular modeling on the complexes with the NOP
lower energy structure of the protein–ligand complex was receptor suggested that the non-conservative aminoacid
predicted together with the biologically active conformation Thr305 together with Asp130 can be considered of critical
of each ligand.
importance in the interaction of spiropiperidines with
This procedure highlighted the possibility that each cis N1- NOP receptor. The recent hypothesis that efficacy of
H compound 3d, 3e, 4d and 4e could form two isoenergetic spiropiperidines is also related to a lipophilic interaction be-
complexes with the NOP receptor, while N1-methylated 3m, tween the cycloalkyl substituent and the receptorial hy-
3n, 4m and 4n presented only one way of docking to the re- drophobic second pocket neighbouring the Asp130,27) has
ceptor. All the generated protein-ligand complexes shared the also been confirmed.
following interactions:
In summary, our series of compounds could be further ex-
a) a salt-bridge between Asp130 and the protonated ploited as tools for studying receptor interactions as related
piperidine nitrogen. This interaction has been established to to biological efficacy.
be fundamental amongst many NOP ligands21,22) and it is of
Experimental
utter importance in the binding of nociceptin itself to its re-
ceptor.18,21)
Melting points were determined on a Köfler hot stage apparatus, unless
otherwise stated, and are uncorrected. Column chromatographic separations
were accomplished on Merck silica gel (70—230 mesh) or on Merck alu-
minium oxide 90. The purity of each compound was checked on silica gel C.
Erba 60 F254 or Merck aluminium oxide 60 F254 (type E) plates and spots
were located by UV light. Sodium sulfate was used to dry organic solutions.
Analyses indicated by the symbols of the elements were within ꢃ0.4% of
the theoretical values.
b) various dispersive interactions between the aromatic
moiety and the lipophilic residues in the first pocket and
other dispersive interactions between the alkylcyclohexyl
substituent of the ligands and the lipophilic residues in the
second pocket.
Moreover the first complex of cis compounds 3d, 3e, 4d
and 4e with NOP receptor showed a hydrogen bond (2.5—
2.7 Å) between the carbonyl oxygen of the quinazolinone
ring or triazoloquinazoline N1-nitrogen and the hydroxyl
group of Thr305, and a quite strong hydrogen bond (1.5 Å)
between the hydrogen at the N1-position of the quinazolinone
ring and the carbonyl oxygen of Cys200 (Fig. 7B1).
In the second complex the same compounds pointed the
N1-H group to Thr305 forming a hydrogen bond acting as
donors (Fig. 7B2).
1
The H-NMR spectra and COSY experiments were performed on Bruker
Avance 700 and 400 instruments in pyridine-d5, in order to improve the
spectral resolution of the aliphatic region, or in CDCl3 or DMSO-d6 solu-
tion; all values are reported in ppm (d) and standard abbreviations were used
(aꢁapparent; bꢁbroad; dꢁdoublet; ddꢁdoublet of doublets; dtꢁdoublet of
triplets; mꢁmultiplet; qꢁquadruplet; qtꢁquintet, sꢁsinglet; shꢁsharp,
tꢁtriplet; ttꢁtriplet of triplets, uꢁunresolved).
Electron Ionisation Mass spectra were recorded on a HP 59980 B spec-
trometer operating at 70 eV.
Amantadine was obtained from its commercial hydrochloride by displace-
ment with aqueous sodium hydroxide. The 5H-10,11-dihydrodibenzo-
[a,d]cyclohepten-5-amine was prepared according to the literature.31) The
4-substituted cyclohexylamines were obtained, in the form of cis–trans iso-
meric mixture,24) by reduction with lithium aluminium hydride of the corre-
sponding oximes, which was performed in refluxing tetrahydrofuran accord-
These results agreed with the models proposed for the
complexes between NOP receptor and nociceptin18) and NOP
receptor with other potent agonists.22)
a ; 1-benzyl-4-piperidone 2e and 1-
conventional procedure32)
N1-Methylated cis 3m, 3n, 4m and 4n bound the receptor
by a moderate interaction of the quinazolinone carbonyl
(3m, n) or triazoloquinazoline C10bꢁN1 (4m, n) groups with
Thr305 hydroxyl group.
ing to
phenethyl-4-piperidone 2f were purchased by Fluka.
General Procedure for the Preparation of the 1-Substituted 4-Piperi-
dones 2 To a suspension of the appropriate amine (0.02 mol) and sodium
carbonate (1.4 g, 0.013 mol) in refluxing ethanol (60 ml) under stirring, was
dropwise added a solution of 123) (8.1 g, 0.03 mol) in water (20 ml), and the
mixture refluxed for 2 h. The resulting solution was evaporated in vacuo to
remove ethanol, then strongly alkalinized with 20% aqueous sodium hydrox-
ide and extracted with ethyl acetate. The organic phase was dried over
sodium sulfate and evaporated in vacuo. The residue was chromatographed
on silica gel by eluting with a 1 : 1 ethyl acetate–hexane mixture in the case
of 2e or on aluminium oxide by eluting with a 1 : 3 ethyl acetate–hexane
mixture for the other compounds.
cis-1-(4-Methylcyclohexyl)-4-piperidone (2a cis) Compound 2a cis was
obtained from 4-methylcyclohexylamine (isomeric mixture) in 20% yield,
pale yellow oil. 1H-NMR (Pyridine-d5) d: 0.87 (3H, d, 4ꢀ-CH3), 1.38 (6H, m,
H-2ꢀax, H-6ꢀax, H-3ꢀ, H-5ꢀ), 1.56 (3H, m, H-2ꢀeq, H-6ꢀeq, H-4ꢀeq), 2.26 (1H, t,
H-1ꢀax, Jꢁ8.2 Hz), 2.40 (4H, t, H-3, H-5), 2.65 (4H, t, H-2, H-6). MS m/z:
195 (Mꢁ), 170, 138. Anal. Calcd for C12H21NO: C, 73.80; H, 10.84; N, 7.17.
These results highlighted the ligand molecular groups in-
volved in the binding affinities but did not provide any infor-
mation about structural requirements responsible for intrinsic
activity. In fact on the basis of molecular modeling studies
we could not explain why only the methylated cis tert-
butylderivatives 3n and 4n showed antagonist activity. In this
series of compounds we can only hypothize that the simulta-
neous presence of chemical groups as methyl and tert-butyl
conferred to the ligands an optimally sized and directed con-
formation able to inactivate the receptor.

May 2006
617
in 15% yield, white solids from hexane, mp 66—67 °C. 1H-NMR (Pyridine-
d5) d: 0.80 (9H, s, tert-butyl), 0.84 (1H, t, H-4ꢀax, Jꢁ12.0 Hz), 0.88 (2H, q,
H-3ꢀax, H-5ꢀax, Jꢁ11.9 Hz), 1.13 (2H, q, H-2ꢀax, H-6ꢀax, Jꢁ12.3 Hz), 1.69
(2H, d, H-3ꢀeq, H-5ꢀeq, Jꢁ11.7 Hz), 1.80 (2H, d, H-2ꢀeq, H-6ꢀeq, Jꢁ11.5 Hz),
2.31 (1H, tt, H-1ꢀax, Jvic diaxꢁ11.7 Hz, Jvic ax eqꢁ3.1 Hz), 2.42 (4H, t, H-3, H-
5), 2.72 (4H, t, H-2, H-6). MS m/z: 237 (Mꢇ), 222, 180, 166, 138. Anal.
Calcd for C15H27NO: C, 75.89; H, 11.47; N, 5.90. Found: C, 76.03; H,
11.70; N, 5.77.
1-(1-Adamantyl)-4-piperidone (2h) Compound 2h was obtained from
amantadine in 39% yield, white solids from hexane, mp 85—86 °C. 1H-
NMR (Pyridine-d5) d: 1.13 (3H, d, H-2ꢀax, H-8ꢀax, H-9ꢀax, Jgemꢁ12.1 Hz),
1.19 (3H, d, H-2ꢀeq, H-8ꢀeq, H-9ꢀeq, Jgemꢁ12.1 Hz), 1.22 (6H, bs, H-4ꢀ, H-6ꢀ,
H-10ꢀ), 1.60 (3H, bs, H-3ꢀeq, H-5ꢀeq, H-7ꢀeq), 2.02 (4H, t, H-3, H-5), 2.36
(4H, t, H-2, H-6). MS m/z: 233 (Mꢇ), 190, 176, 164, 135, 106. Anal. Calcd
for C15H23NO: C, 77.20; H, 9.94; N, 6.00. Found: C, 76.96; H, 10.27; N,
5.91.
Found: C, 74.02; H, 10.49; N, 7.04.
trans-1-(4-Methylcyclohexyl)-4-piperidone (2a trans) Compound 2a
trans was obtained from 4-methylcyclohexylamine (isomeric mixture) in
1
21% yield, pale yellow oil. H-NMR (Pyridine-d5) d: 0.81 (3H, d, 4ꢀ-CH3),
0.85 (2H, m, H-3ꢀax, H-5ꢀax, Jꢁ12.9 Hz), 1.15 (3H, overlapped q and m, H-
2ꢀax, H-6ꢀax, H-4ꢀax, Jꢁ12.4 Hz, Jꢁ2.3 Hz,), 1.61 (2H, d, H-3ꢀeq, H-5ꢀeq, Jꢁ
13.1 Hz), 1.73 (2H, d, H-2ꢀeq, H-6ꢀeq, Jꢁ11.6 Hz), 2.33 (1H, t, H-1ꢀax, Jdiaxꢁ
11.7 Hz, Jax-eqꢁ3.0 Hz), 2.40 (4H, t, H-3, H-5), 2.67 (4H, t, H-2, H-6). MS
m/z: 195 (Mꢇ), 170, 138. Anal. Calcd for C12H21NO: C, 73.80; H, 10.84; N,
7.17. Found: C, 73.98; H, 11.00; N, 7.49.
cis-1-(4-Ethylcyclohexyl)-4-piperidone (2b cis) Compound 2b cis was
obtained from 4-ethylcyclohexylamine (isomeric mixture) in 30%, yield,
pale yellow oil. 1H-NMR (Pyridine-d5) d: 0.83 (3H, t, ethyl CH3), 1.23 (2H,
qt, 4ꢀ-ethyl CH2), 1.27 (1H, m, H-4ꢀeq, Jꢁ5.0 Hz), 1.37 (4H, m, H-2ꢀax, H-
3ꢀax, H-5ꢀax, H-6ꢀax), 1.47 (2H, bm, H-3ꢀeq, H-5ꢀeq), 1.52 (2H, bd, H-2ꢀeq, H-
6ꢀeq), 2.29 (1H, t, H-1ꢀax, Jdiaxꢁ8.0 Hz, Jax-eqꢁ5.3 Hz), 2.41 (4H, t, H-3, H-5),
2.66 (4H, t, H-2, H-6). MS m/z: 209 (Mꢇ), 170, 138. Anal. Calcd for
C13H23NO: C, 74.59; H, 11.08; N, 6.69. Found: C, 74.48; H, 11.42; N, 6.56.
trans-1-(4-Ethylcyclohexyl)-4-piperidone (2b trans) Compound 2b trans
was obtained from 4-ethylcyclohexylamine (isomeric mixture) in 11% yield,
(5H-10,11-Dihydrodibenzo[a,d]cyclohepten-5-yl)-4-piperidone
(2i)
Compound 2i was obtained from 5H-10,11-dihydrodibenzo[a,d]cyclohep-
1
ten-5-amine in 50% yield, white solid from ethanol, mp 116—118 °C. H-
NMR (CDCl3) d: 2.40 (4H, t, H-3, H-5), 2.65 (4H, t, H-2, H-6), 2.87 (2H,
m, H-10ꢀ, H-11ꢀ), 4.10 (2H, m, H-10ꢀ, H-11ꢀ), 4.12 (1H, s, H-5ꢀ), 7.18 (8H,
m, aromatics). MS m/z: 291 (Mꢇ), 192, 178, 165, 115. Anal. Calcd for
C20H21NO: C, 82.44; H, 7.27; N, 4.81. Found: C, 82.39; H, 7.49; N, 5.05.
General Procedure for the Preparation of the Spiro[piperidine-
4,2ꢀ(1ꢀH)-quinazolin]-4ꢀ(3ꢀH)-ones 3a—i and of the Spiro[piperidine-
4,5ꢀ-[1,2,4]triazolo[1,5-c]quinazolines] 4a—i A solution of the appropri-
ate piperidone 2 (0.01 mol) and anthranylamide (1.4 g, 0.01 mol) for com-
pounds 3a—i or 3-(2-aminophenyl)-[1,2,4]triazole25) (1.6 g, 0.01 mol) for
compounds 4a—i in acetic acid (14 ml) with two drops of sulfuric acid, was
kept under stirring at room temperature for 2—4 h; then the mixture was di-
luted with water and alkalinized with 8% aqueous sodium hydroxide; the re-
sulting precipitate was collected by filtration, washed with water, then with
diethyl ether and dried in vacuo.
1
pale yellow oil. H-NMR (Pyridine-d5) d: 0.81 (5H, overlapped m and t, H-
3ꢀax, H-5ꢀax, ethyl CH3), 0.92 (1H, um, H-4ꢀax), 1.14 (4H, m, H-2ꢀax, H-6ꢀax,
4ꢀ-ethyl CH2), 1.69 (2H, d, H-3ꢀeq, H-5ꢀeq, Jgemꢁ12.4 Hz), 1.78 (2H,
d, H-2ꢀeq, H-6ꢀeq,
Jgemꢁ11.9 Hz), 2.34 (1H, t, H-1ꢀax, Jdiaxꢁ11.7 Hz,
J
ax-eqꢁ3.1 Hz), 2.41 (4H, t, H-3, H-5), 2.68 (4H, t, H-2, H-6). MS m/z: 209
(Mꢇ), 170, 138. Anal. Calcd for C13H23NO: C, 74.59; H, 11.08; N, 6.69.
Found: C, 74.98; H, 10.91; N, 6.43.
cis-1-(4-n-Propylcyclohexyl)-4-piperidone (2c cis) Compound 2c cis
was obtained from 4-n-propylcyclohexylamine (isomeric mixture) in 11%
1
yield, pale yellow oil. H-NMR (Pyridine-d5) d: 0.87 (3H, t, n-propyl CH3),
1.24 (4H, bm, n-propyl CH2–CH2), 1.32—1.60 (9H, m, H-2ꢀ, H-3ꢀ, H-5ꢀ, H-
6ꢀ, H-4ꢀ), 2.30 (1H, t, H-1ꢀ, Jꢁ7.6 Hz), 2.42 (4H, t, H-3, H-5), 2.67 (4H, t,
H-2, H-6). MS m/z: 223 (Mꢇ), 170, 138. Anal. Calcd for C14H25NO: C,
75.28; H, 11.28; N, 6.27. Found: C, 75.59; H, 11.40; N, 6.52.
cis-1-(4-Methylcyclohexyl)-spiro[piperidine-4,2ꢀ(1ꢀH)-quinazolin]-
4ꢀ(3ꢀH)-one (3a cis) Compound 3a cis was obtained from 2a cis in 47%
trans-1-(4-n-Propylcyclohexyl)-4-piperidone (2c trans) Compound 2c
trans was obtained from 4-n-propylcyclohexylamine (isomeric mixture) in
1
yield, white solids from ethyl acetate, mp 210—212 °C. H-NMR (DMSO-
1
11% yield, pale yellow oil. H-NMR (Pyridine-d5) d: 0.86 (5H, overlapped
d6) d: 0.88 (3H, d, 4ꢈ-CH3), 1.39 (7H, m, H-3ꢈ, H-5ꢈ, H-2ꢈax, H-6ꢈax, H-4ꢈeq),
1.63 (2H, m, H-2ꢈeq, H-6ꢈeq), 1.76 (4H, m, H-3, H-5), 2.22 (1H, t, H-1ꢈax,
Jꢁ7.4 Hz), 2.58 (4H, m, partially under solvent signal, H-2, H-6), 6.62 (1H,
t, H-6ꢀ, Jorthoꢁ7.1 Hz), 6.63 (1H, s, 1ꢀ-NH), 6.80 (1H, d, H-8ꢀ, Jorthoꢁ
8.1 Hz), 7.20 (1H, t, H-7ꢀ, Jorthoꢁ7.9 Hz), 7.56 (1H, d, H-5ꢀ, Jorthoꢁ7.6 Hz),
7.93 (1H, s, 3ꢀ-NH). MS m/z: 313 (Mꢇ), 296, 256, 228, 217, 200, 189, 173,
160, 152, 141, 126, 120, 98. Anal. Calcd for C19H27N3O: C, 72.80; H, 8.68;
N, 13.41. Found: C, 73.03; H, 8.34; N, 13.29.
m and t, H-3ꢀax, H-5ꢀax, n-propyl CH3), 1.08 (3H, m, H-4ꢀ, n-propyl CH2),
1.17 (2H, q, H-2ꢀax, H-6ꢀax, Jꢁ12.4 Hz, Jꢁ3.2 Hz), 1.25 (2H, qt, 4ꢀ-n-propyl
CH2), 1.72 (2H, d, H-3ꢀeq, H-5ꢀeq, Jgemꢁ12.7 Hz), 1.77 (2H, d, H-2ꢀeq, H-6ꢀeq,
J
gemꢁ13.5 Hz), 2.37 (1H, t, H-1ꢀax, Jdiaxꢁ11.9 Hz, Jax-eqꢁ3.4 Hz), 2.41 (4H,
t, H-3, H-5), 2.69 (4H, t, H-2, H-6). MS m/z: 223 (Mꢇ), 170, 138. Anal.
Calcd for C14H25NO: C, 75.28; H, 11.28; N, 6.27. Found: C, 75.07; H,
11.18; N, 6.41.
cis-1-(4-iso-Propylcyclohexyl)-4-piperidone (2d cis) Compound 2d cis
was obtained from 4-iso-propylcyclohexylamine (isomeric mixture) in 11%
yield, pale yellow oil. 1H-NMR (Pyridine-d5) d: 0.80 (6H, d, iso-propyl
CH3), 1.02 (1H, m, H-4ꢀax), 1.32 (4H, m, H-2ꢀax, H-6ꢀax, H-3ꢀeq, H-5ꢀeq), 1.48
(1H, m, iso-propyl CH), 1.57 (2H, m, H-3ꢀax, H-5ꢀax), 1.63 (2H, m, H-2ꢀeq,
H-6ꢀeq), 2.28 (1H, as, H-1ꢀeq), 2.42 (4H, t, H-3, H-5), 2.66 (4H, t, H-2, H-6).
MS m/z: 223 (Mꢇ), 170, 138. Anal. Calcd for C14H25NO: C, 75.28; H, 11.28;
N, 6.27. Found: C, 75.36; H, 11.39; N, 5.97.
trans-1-(4-iso-Propylcyclohexyl)-4-piperidone (2d trans) Compound
2d trans was obtained from 4-iso-propylcyclohexylamine (isomeric mixture)
in 10% yield, pale yellow oil. 1H-NMR (Pyridine-d5) d: 0.81 (6H, d, iso-
propyl CH3), 0.88 (3H, m, H-3ꢀeq, H-5ꢀeq, H-4ꢀax), 1.15 (2H, q, H-2ꢀax, H-
6ꢀax, Jꢁ10.4 Hz, Jꢁ3.2 Hz), 1.32 (1H, m, iso-propyl CH), 1.65 (2H, ut, H-
3ꢀax, H-5ꢀax), 1.79 (2H, d, H-2ꢀeq, H-6ꢀeq, Jgemꢁ12.0 Hz), 2.33 (1H, t, H-1ꢀax,
trans-1-(4-Methylcyclohexyl)-spiro[piperidine-4,2ꢀ(1ꢀH)-quinazolin]-
4ꢀ(3ꢀH)-one (3a trans) Compound 3a trans was obtained from 2a trans in
47% yield, white solids from ethyl acetate, mp 215—218 °C. 1H-NMR
(DMSO-d6) d: 0.86 (5H, overlapped m and d, H-3ꢈeq, H-5ꢈeq, 4ꢈ-CH3), 1.24
(2H, m, H-2ꢈax, H-6ꢈax), 1.39 (1H, at, H-4ꢈax, Jꢁ10.1 Hz), 1.74 (8H, m, H-3,
H-5, H-2ꢈeq, H-6ꢈeq, H-3ꢈax, H-5ꢈax), 2.24 (1H, t, H-1ꢈax, Jꢁ11.8 Hz), 2.54
(4H, m, H-2, H-6), 6.62 (1H, t, H-6ꢀ, Jorthoꢁ7.5 Hz), 6.63 (1H, s, 1ꢀ-NH),
6.80 (1H, d, H-8ꢀ, Jorthoꢁ8.2 Hz), 7.22 (1H, t, H-7ꢀ, Jorthoꢁ7.3 Hz), 7.56 (1H,
d, H-5ꢀ, Jorthoꢁ7.8 Hz), 7.95 (1H, s, 3ꢀ-NH). MS m/z: 313 (Mꢇ), 296, 256,
228, 217, 189, 173, 160, 141, 126, 120, 112, 98. Anal. Calcd for C19H27N3O:
C, 72.80; H, 8.68; N, 13.41. Found: C, 72.49; H, 9.00; N, 13.78.
cis-1-(4-Ethylcyclohexyl)-spiro[piperidine-4,2ꢀ(1ꢀH)-quinazolin]-
4ꢀ(3ꢀH)-one (3b cis) Compound 3b cis was obtained from 2b cis in 48%
1
yield, white solids from ethyl acetate, mp 210—212 °C. H-NMR (DMSO-
J
diaxꢁ11.6 Hz, Jax-eqꢁ3.6 Hz), 2.41 (4H, t, H-3, H-5), 2.71 (4H, t, H-2, H-6).
d6) d: 0.82 (3H, t, ethyl CH3), 1.27 (2H, qt, ethyl 4ꢈ-CH2), 1.39 (7H, m, H-
3ꢈ, H-5ꢈ, H-2ꢈax, H-6ꢈax, H-4ꢈeq), 1.58 (2H, m, H-2ꢈeq, H-6ꢈeq), 7.91 (1H, s,
3ꢀ-NH), 1.75 (4H, m, H-3, H-5), 2.24 (1H, t, H-1ꢈax, Jꢁ7.4 Hz), 2.49 (4H, m
under solvent signal, H-2, H-6), 6.61 (1H, s, 1ꢀ-NH), 6.62 (1H, t, H-6ꢀ,
MS m/z: 223 (Mꢇ), 170, 138. Anal. Calcd for C14H25NO: C, 75.28; H, 11.28;
N, 6.27. Found: C, 74.95; H, 10.91; N, 6.08.
cis-1-(4-tert-Butylcyclohexyl)-4-piperidone (2e cis) Compound 2e cis
was obtained from 4-tert-butylcyclohexylamine (isomeric mixture) in 14%
yield, white solids from hexane, mp 57—59 °C. 1H-NMR (Pyridine-d5) d:
0.85 (9H, s, tert-butyl), 1.02 (1H, m, H-4ꢀax), 1.25 (2H, t, H-3ꢀax, H-5ꢀax,
J
J
orthoꢁ7.7 Hz), 6.79 (1H, d, H-8ꢀ,
Jorthoꢁ8.1 Hz), 7.21 (1H, t, H-7ꢀ,
orthoꢁ7.9 Hz), 7.55 (1H, d, H-5ꢀ, Jorthoꢁ7.7 Hz). MS m/z: 327 (Mꢇ), 310,
256, 228, 217, 189, 173, 160, 155, 140, 126, 120, 110. Anal. Calcd for
C20H29N3O: C, 73.35; H, 8.93; N, 12.83. Found: C, 73.45; H, 8.59; N, 12.52.
trans-1-(4-Ethylcyclohexyl)-spiro[piperidine-4,2ꢀ(1ꢀH)-quinazolin]-
4ꢀ(3ꢀH)-one (3b trans) Compound 3b trans was obtained from 2b trans in
48% yield, white solids from ethyl acetate, mp 216—218 °C. 1H-NMR
(DMSO-d6) d: 0.83 (5H, overlapped m and t, H-3ꢈeq, H-5ꢈeq, ethyl CH3),
1.14 (4H, m, H-2ꢈax, H-6ꢈax, ethyl 4ꢈ-CH2), 1.40 (1H, at, H-4ꢈax, Jꢁ7.9 Hz),
1.74 (8H, sh m, H-3, H-5, H-2ꢈeq, H-6ꢈeq, H-3ꢈax, H-5ꢈax), 2.23 (1H, t, H-1ꢈax,
Jꢁ10.7 Hz), 2.54 (4H, m, H-2, H-6), 6.61 (1H, s, 1ꢀ-NH), 6.62 (1H, t, H-6ꢀ,
Jgemꢁ13.4 Hz, Jvic diaxꢁ12.9 Hz, Jvic ax eqꢁ2.8 Hz), 1.37 (2H, sh m, H-3ꢀeq, H-
5ꢀeq), 1.39 (2H, t, H-2ꢀax, H-6ꢀax), 1.92 (2H, dd, H-2ꢀeq, H-6ꢀeq, Jgemꢁ14.7 Hz,
Jꢁ2.1 Hz), 2.21 (1H, sh m, H-1ꢀeq, Jꢁ2.8 Hz), 2.38 (4H, sh m, H-3, H-5),
2.64 (4H, sh m, H-2, H-6). MS m/z: 237 (Mꢇ), 222, 180, 170, 166, 138.
Anal. Calcd for C15H27NO: C, 75.89; H, 11.47; N, 5.90. Found: C, 75.50; H,
11.36; N, 6.12.
trans-1-(4-tert-Butylcyclohexyl)-4-piperidone (2e trans) Compound
2e trans was obtained from 4-tert-butylcyclohexylamine (isomeric mixture)

618
Vol. 54, No. 5
11.82. Found: C, 74.58; H, 9.68; N, 12.00.
Jorthoꢁ7.5 Hz), 6.80 (1H, d, H-8ꢀ, Jorthoꢁ8.1 Hz), 7.21 (1H, t, H-7ꢀ,
1-Benzylspiro[piperidine-4,2ꢀ(1ꢀH)-quinazolin]-4ꢀ(3ꢀH)-one (3f) Com-
pound 3f was obtained from 2f in 49% yield, off-white solids from dimethyl-
formamide, mp 255—257 °C (lit.33) 262.0—262.5 °C from methanol). 1H-
NMR (DMSO-d6) d: 1.84 (4H, bm, H-3, H-5), 2.76 (4H, bm, H-2, H-6),
3.49 (2H, s, benzyl CH2), 6.65 (1H, t, H-6ꢀ, Jorthoꢁ7.4 Hz), 6.74 (1H, s, 1ꢀ-
NH), 6.80 (1H, d, H-8ꢀ, Jorthoꢁ8.1 Hz), 7.24 (6H, m, H-7ꢀ, benzyl aromat-
ics), 7.58 (1H, d, H-5ꢀ, Jorthoꢁ7.7 Hz), 8.04 (1H, s, 3ꢀ-NH). MS m/z: 307
(Mꢇ), 290, 216, 189, 173, 161, 146, 134, 120, 106, 91. Anal. Calcd for
C19H21N3O: C, 74.24; H, 6.89; N, 13.67. Found: C, 74.55; H, 6.53; N, 13.44.
J
orthoꢁ7.5 Hz), 7.55 (1H, d, H-5ꢀ, Jorthoꢁ7.7 Hz), 7.92 (1H, s, 3ꢀ-NH). MS
m/z: 327 (Mꢇ), 310, 256, 228, 217, 189, 173, 160, 155, 140, 126, 120, 110.
Anal. Calcd for C20H29N3O: C, 73.35; H, 8.93; N, 12.83. Found: C, 73.53; H,
9.15; N, 13.04.
cis-1-(4-n-Propylcyclohexyl)-spiro[piperidine-4,2ꢀ(1ꢀH)-quinazolin]-
4ꢀ(3ꢀH)-one (3c cis) Compound 3c cis was obtained from 2c cis in 49%
yield, white solids from ethyl acetate, mp 208—210 °C. H-NMR (DMSO-
1
d6) d: 0.81 (3H, t, n-propyl CH3), 1.22 (4H, m, H-2ꢈax, H-6ꢈax, n-propyl
CH2), 1.42 (7H, m, H-3ꢈ, H-5ꢈ, H-4ꢈ, 4ꢈ-n-propyl CH2), 1.52 (2H, m, H-2ꢈeq,
H-6ꢈeq), 1.84 (4H, m, H-3, H-5), 2.23 (1H, sh m, H-1ꢈeq, Jꢁ2.7 Hz), 2.60
(4H, m, H-2, H-6), 6.62 (1H, t, H-6ꢀ, Jorthoꢁ7.2 Hz), 6.67 (1H, s, 1ꢀ-NH),
6.80 (1H, d, H-8ꢀ, Jorthoꢁ8.2 Hz), 7.20 (1H, t, H-7ꢀ, Jorthoꢁ8.0 Hz), 7.57 (1H,
d, H-5ꢀ, Jorthoꢁ7.8 Hz), 7.94 (1H, s, 3ꢀ-NH). MS m/z: 341 (Mꢇ), 324, 256,
228, 217, 189, 173, 160, 154, 140, 124, 120. Anal. Calcd for C21H31N3O: C,
73.86; H, 9.15; N, 12.31. Found: C, 74.02; H, 8.88; N, 11.99.
trans-1-(4-n-Propylcyclohexyl)-spiro[piperidine-4,2ꢀ(1ꢀH)-quina-
zolin]-4ꢀ(3ꢀH)-one (3c trans) Compound 3c trans was obtained from
2c trans in 49% yield, white solids from ethyl acetate, mp 224—226 °C. 1H-
NMR (DMSO-d6) d: 0.83 (5H, bt, n-propyl CH3, H-3ꢈeq, H-5ꢈeq), 1.14 (3H,
m, n-propyl CH2, H-4ꢈax), 1.25 (4H, m, n-propyl 4ꢈ-CH2, H-2ꢈax, H-6ꢈax),
1.73 (8H, m, H-3, H-5, H-2ꢈeq, H-6ꢈeq, H-3ꢈax, H-5ꢈax), 2.22 (1H, t, H-1ꢈax,
1-Phenethylspiro[piperidine-4,2ꢀ(1ꢀH)-quinazolin]-4ꢀ(3ꢀH)-one
(3g)
Compound 3g was obtained from 2g in 51% yield, white solids from
1
methanol, mp 170—173 °C. H-NMR (DMSO-d6) d: 1.77 (4H, m, H-3, H-
5), 2.49 (6H, m under solvent signal, H-2, H-6, phenethyl N–CH2), 3.47
(2H, t, phenethyl CH2), 6.62 (1H, t, H-6ꢀ, Jorthoꢁ7.4 Hz), 6.68 (1H, s, 1ꢀ-
NH), 6.80 (1H, d, H-8ꢀ, Jorthoꢁ8.0 Hz), 7.28 (6H, m, H-7ꢀ, phenethyl aromat-
ics), 7.58 (1H, d, H-5ꢀ, Jorthoꢁ7.5 Hz), 7.97 (1H, s, 3ꢀ-NH). MS m/z: 321
(Mꢇ), 304, 230, 217, 202, 189, 173, 160, 134, 120, 91. Anal. Calcd for
C20H23N3O: C, 74.73; H, 7.21; N, 13.08. Found: C, 74.83; H, 6.82; N, 13.36.
1-(1-Adamantyl)-spiro[piperidine-4,2ꢀ(1ꢀH)-quinazolin]-4ꢀ(3ꢀH)-one
(3h) Compound 3h was obtained from 2h in 44% yield, white solids from
ethyl acetate, mp 277—280 °C (dec.). 1H-NMR (DMSO-d6) d: 1.58, 1.65,
1.74, (16H, three as, H-3, H-5, H-4ꢈ, H-6ꢈ, H-10ꢈ, H-2ꢈ, H-8ꢈ, H-9ꢈ), 2.04
(3H, bs, H-3ꢈ, H-5ꢈ, H-7ꢈ), 2.59 (2H, m, H-2ax, H-6ax,), 2.71 (2H, m, H-2eq,
H-6eq), 6.63 (2H, overlapped s and t, 1ꢀ-NH, H-6ꢀ, Jorthoꢁ7.6 Hz), 6.80 (1H,
d, H-8ꢀ, Jorthoꢁ7.7 Hz), 7.22 (1H, dt, H-7ꢀ, Jorthoꢁ7.3 Hz, Jmetaꢁ1.6 Hz), 7.95
(1H, s, NH), 7.56 (1H, dd, H-5ꢀ, Jorthoꢁ7.7 Hz, Jmetaꢁ1.5 Hz). MS m/z: 351
(Mꢇ), 334, 217, 194, 179, 135, 122. Anal. Calcd for C22H29N3O: C, 75.17;
H, 8.32; N, 11.96. Found: C, 74.92; H, 7.96; N, 12.08.
Jdiaxꢁ10.6 Hz), 2.51 (4H, m, H-2, H-6), 6.62 (1H, t, H-6ꢀ, Jorthoꢁ7.6 Hz),
6.65 (1H, s, 1ꢀ-NH), 6.79 (1H, d, H-8ꢀ, Jorthoꢁ8.1 Hz), 7.22 (1H, t, H-7ꢀ,
J
orthoꢁ7.3 Hz), 7.55 (1H, d, H-5ꢀ, Jorthoꢁ7.6 Hz), 7.95 (1H, s, 3ꢀ-NH). MS
m/z: 341 (Mꢇ), 324, 256, 228, 217, 189, 173, 169, 160, 154, 140, 124, 120.
Anal. Calcd for C21H31N3O: C, 73.86; H, 9.15; N, 12.31. Found: C, 73.49; H,
8.93; N, 12.04.
cis-1-(4-iso-Propylcyclohexyl)-spiro[piperidine-4,2ꢀ(1ꢀH)-quinazolin]-
4ꢀ(3ꢀH)-one (3d cis) Compound 3d cis was obtained from 2d cis in 64%
yield, white solids from ethyl acetate, mp 232—234 °C. H-NMR (DMSO-
1-(5H-10,11-Dihydrodibenzo[a,d]cyclohepten-5-yl)-spiro[piperidine-
4,2ꢀ(1ꢀH)-quinazolin]-4ꢀ(3ꢀH)-one (3i) Compound 3i was obtained from
2i in 51% yield, white solids from ethyl acetate, mp 280—282 °C; 1H-NMR
(DMSO-d6) d: 1.72 (4H, m, H-3, H-5), 2.40 (4H, m, H-2, H-6), 2.73 (2H, m,
H-10ꢈ, H-11ꢈ), 3.90 (2H, m, H-10ꢈ, H-11ꢈ), 4.10 (1H, s, H-5ꢈ), 6.65 (1H, t,
H-6ꢀ, Jorthoꢁ7.7 Hz), 6.66 (1H, s, 1ꢀ-NH), 6.80 (1H, d, H-8ꢀ, Jorthoꢁ8.1 Hz),
7.13 (9H, m, H-7ꢀ, dibenzosuberyl aromatics), 7.54 (1H, dd, H-5ꢀ,
1
d6) d: 0.83 (6H, d, iso-propyl CH3), 1.07 (1H, bm, H-4ꢈ), 1.31 (2H, m, H-
3ꢈeq, H-5ꢈeq,), 1.37 (2H, d, H-2ꢈax, H-6ꢈax), 1.47 (3H, m, H-3ꢈax, H-5ꢈax, iso-
propyl CH), 1.69 (2H, m, H-2ꢈeq, H-6ꢈeq), 1.76 (4H, m, H-3, H-5), 2.24 (1H,
sh m, H-1ꢈeq, Jꢁ2.8 Hz), 2.44 (2H, m, H-2ax, H-6ax), 2.58 (2H, d, H-2eq, H-
6eq), 6.61 (1H, s, 1ꢀ-NH), 6.64 (1H, t, H-6ꢀ, Jorthoꢁ7.3 Hz), 6.79 (1H, d, H-
8ꢀ, Jorthoꢁ7.9 Hz), 7.21 (1H, t, H-7ꢀ, Jorthoꢁ7.5 Hz), 7.55 (1H, d, H-5ꢀ,
J
orthoꢁ7.7 Hz, Jmetaꢁ1.5 Hz), 7.88 (1H, s, 3ꢀ-NH). MS m/z: 409 (Mꢇ), 218,
J
orthoꢁ7.6 Hz), 7.89 (1H, s, 3ꢀ-NH). MS m/z: 341 (Mꢆ), 324, 256, 228, 217,
193, 178, 160, 115. Anal. Calcd for C27H27N3O: C, 79.18; H, 6.65; N, 10.26.
Found: C, 78.85; H, 6.94; N, 10.39.
189, 173, 160, 154, 140, 120, 110. Anal. Calcd for C21H31N3O: C, 73.86; H,
9.15; N, 12.31. Found: C, 74.08; H, 9.37; N, 12.53.
cis-1-(4-Methylcyclohexyl)-spiro[piperidine-4,5ꢀ(6ꢀH)-[1,2,4]tria-
zolo[1,5-c]quinazoline] (4a cis) Compound 4a cis was obtained from
trans-1-(4-iso-Propylcyclohexyl)-spiro[piperidine-4,2ꢀ(1ꢀH)-quina-
zolin]-4ꢀ(3ꢀH)-one (3d trans) Compound 3d trans was obtained from
2d trans in 75% yield, white solids from ethyl acetate, mp 242—244 °C. 1H-
NMR (DMSO-d6) d: 0.82 (6H, d, iso-propyl CH3), 0.95 (3H, m, H-3ꢈeq, H-
4ꢈax, H-5ꢈeq), 1.17 (2H, dd, H-2ꢈax, H-6ꢈax), 1.38 (1H, m, iso-propyl CH),
1.73—1.82 (8H, m, H-3, H-5, H-2ꢈeq, H-6ꢈeq, H-3ꢈax, H-5ꢈax), 2.20 (1H, t, H-
1ꢈax, Jdiaxꢁ12.0 Hz), 2.56 (4H, m, H-2, H-6), 6.63 (2H, m, H-6ꢀ, 1ꢀ-NH),
6.79 (1H, d, H-8ꢀ, Jorthoꢁ8.0 Hz), 7.21 (1H, t, H-7ꢀ, Jorthoꢁ7.1 Hz), 7.55 (1H,
d, H-5ꢀ, Jorthoꢁ7.5 Hz), 7.90 (1H, s, 3ꢀ-NH). MS m/z: 341 (Mꢇ), 324, 256,
228, 217, 189, 173, 169, 160, 154, 140, 138, 120, 110. Anal. Calcd for
C21H31N3O: C, 73.86; H, 9.15; N, 12.31. Found: C, 73.63; H, 8.79; N, 12.66.
cis-1-(4-tert-Butylcyclohexyl)-spiro[piperidine-4,2ꢀ(1ꢀH)-quinazolin]-
4ꢀ(3ꢀH)-one (3e cis) Compound 3e cis was obtained from 2e cis in 40%
1
2a cis in 31% yield, white solids from ethyl acetate, mp 205—207 °C. H-
NMR (Pyridine-d5) d: 0.33 (3H, d, CH3), 0.80—0.85 (6H, m, H-2ꢈeq, H-3ꢈ,
H-5ꢈ, H-6ꢈeq), 1.04—1.08 (3H, m, H-2ꢈax, H-4ꢈ, H-6ꢈax), 1.65 (2H, d, H-3eq,
H-5eq), 1.68 (1H, t, H-1ꢈax Jꢁ7.8 Hz), 2.05 (2H, t, H-3ax, H-5ax), 2.38 (2H, t,
H-2ax, H-6ax), 2.38 (2H, d, H-2eq, H-6eq), 6.94 (1H, t, H-9ꢀ), 7.15 (1H, d, H-
7ꢀ), 7.28 (1H, t, H-8ꢀ), 7.49 (1H, bs, NH), 8.21 (1H, d, H-10ꢀ), 8.34 (1H, s,
H-2ꢀ). MS m/z: 337 (Mꢇ), 280, 225, 213, 192, 178, 126. Anal. Calcd for
C20H27N5: C, 71.18; H, 8.07; N, 20.76. Found: C, 71.02; H, 7.84; N, 20.86.
trans-1-(4-Methylcyclohexyl)-spiro[piperidine-4,5ꢀ(6ꢀH)-[1,2,4]tria-
zolo[1,5-c]quinazoline] (4a trans) Compound 4a trans was obtained from
2a trans in 38% yield, white solids from ethyl acetate, mp 220—225 °C. 1H-
NMR (Pyridine-d5) d: 0.77 (3H, d, CH3), 0.81 (2H, sh m, H-3ꢈeq, H-5ꢈeq),
1.12—1.16 (3H, m, H-2ꢈax, H-4ꢈ, H-6ꢈax), 1.57 (2H, bd, H-3ꢈax, H-5ꢈax), 1.71
(2H, d, H-2ꢈeq, H-6ꢈeq), 2.17 (2H, d, H-3eq, H-5eq), 2.24 (1H, t, H-1ꢈax,
Jꢁ11.2 Hz), 2.64 (2H, t, H-3ax, H-5ax), 2.74 (2H, t, H-2ax, H-6ax), 2.83 (2H,
d, H-2eq, H-6eq), 6.93 (1H, t, H-9ꢀ), 7.18 (1H, d, H-7ꢀ), 7.27 (1H, t, H-8ꢀ),
7.59 (1H, bs, NH), 8.22 (1H, d, H-10ꢀ), 8.34 (1H, s, H-2ꢀ). MS m/z: 337
(Mꢇ), 280, 225, 213, 192, 178, 126. Anal. Calcd for C20H27N5: C, 71.18; H,
8.07; N, 20.76. Found: C, 71.41; H, 8.42; N, 20.48.
1
yield, white solids from ethyl acetate, mp 258—260 °C. H-NMR (DMSO-
d6) d: 0.82 (9H, s, tert-butyl), 1.05 (1H, m, H-4ꢈax), 1.19 (2H, d, H-2ꢈeq, H-
6ꢈeq), 1.30 (2H, t, H-2ꢈax, H-6ꢈax), 1.33 (4H, m, H-3ꢈ, H-5ꢈ), 1.77 (2H, d, H-
3eq, H-5eq), 1.99 (2H, t, H-3ax, H-5ax), 2.22 (1H, sh m, H-1ꢈeq, Jꢁ2.7 Hz ),
2.44 (2H, t, H-2ax, H-6ax), 2.58 (2H, d, H-2eq, H-6eq), 6.63 (1H, t, H-6ꢀ,
Jorthoꢁ7.3 Hz), 6.67 (1H, s, 1ꢀ-NH), 6.81 (1H, d, H-8ꢀ, Jorthoꢁ7.9 Hz), 7.23
(1H, t, H-7ꢀ, Jorthoꢁ7.4 Hz), 7.57 (1H, d, H-5ꢀ, Jorthoꢁ7.6 Hz), 7.94 (1H, s,
3ꢀ-NH). MS m/z: 355 (Mꢇ), 338, 254, 236, 228, 199, 173, 160, 154, 138,
120. Anal. Calcd for C22H33N3O: C, 74.32; H, 9.36; N, 11.82. Found: C,
74.02; H, 9.71; N, 11.49.
cis-1-(4-Ethylcyclohexyl)-spiro[piperidine-4,5ꢀ(6ꢀH)-[1,2,4]tria-
zolo[1,5-c]quinazoline] (4b cis) Compound 4b cis was obtained from
1
2b cis in 37% yield, white solids from ethyl acetate, mp 154—156 °C. H-
NMR (Pyridine-d5) d: 0.81 (3H, t, CH2–CH3), 1.20—1.77 (3H, m, H-4ꢈeq,
CH2–CH3), 1.29—1.39 (4H, m, H-2ꢈax, H-3ꢈax, H-5ꢈax, H-6ꢈax), 1.39—1.41
(2H, m, H-3ꢈeq, H-5ꢈeq), 1.53—1.55 (2H, m, H-2ꢈeq, H-6ꢈeq), 2.17 (2H, d, H-
3eq, H-5eq), 2.23 (1H, t, H-1ꢈax, Jꢁ8.4 Hz), 2.57 (2H, t, H-3ax, H-5ax,), 2.63—
2.66 (2H, m, H-2ax, H-6ax), 2.89 (2H, d, H-2eq, H-6eq), 6.94 (1H, t, H-9ꢀ),
7.18 (1H, d, H-7ꢀ), 7.28 (1H, t, H-8ꢀ), 7.49 (1H, bs, NH), 8.21 (1H, d, H-
10ꢀ), 8.34 (1H, s, H-2ꢀ). MS m/z: 351 (Mꢇ), 280, 225, 213, 192, 155, 140.
Anal. Calcd for C21H29N5: C, 71.76; H, 8.32; N, 19.93. Found: C, 71.53; H,
8.64; N, 19.58.
trans-1-(4-tert-Butylcyclohexyl)-spiro[piperidine-4,2ꢀ(1ꢀH)-quina-
zolin]-4ꢀ(3ꢀH)-one (3e trans) Compound 3e trans was obtained from
2e trans in 40% yield, white solids from ethyl acetate, mp 262—263 °C. 1H-
NMR (DMSO-d6) d: 0.82 (9H, s, tert-butyl), 0.93 (3H, m, H-3ꢈeq, H-4ꢈax, H-
5ꢈeq), 1.19 (2H, t, H-2ꢈax, H-6ꢈax), 1.74—1.86 (8H, m, H-3, H-5, H-2ꢈeq, H-
6ꢈeq, H-3ꢈax, H-5ꢈax), 2.20 (1H, t, H-1ꢈax, Jdiaxꢁ10.2 Hz), 2.57 (4H, m, H-2,
H-6), 6.63 (1H, t, H-6ꢀ, Jorthoꢁ7.3 Hz), 6.65 (1H, s, 1ꢀ-NH), 6.81 (1H, d, H-
8ꢀ, Jorthoꢁ8.0 Hz), 7.22 (1H, t, H-7ꢀ, Jorthoꢁ7.1 Hz), 7.57 (1H, d, H-5ꢀ,
J
orthoꢁ7.5 Hz), 7.96 (1H, s, 3ꢀ-NH). MS m/z: 355 (Mꢇ), 338, 254, 236, 228,
168, 160, 154, 138, 120. Anal. Calcd for C22H33N3O: C, 74.32; H, 9.36; N,
trans-1-(4-Ethylcyclohexyl)-spiro[piperidine-4,5ꢀ(6ꢀH)-[1,2,4]tria-

May 2006
619
zolo[1,5-c]quinazoline] (4b trans) Compound 4b trans was obtained from
2b trans in 41% yield, white solids from ethyl acetate, mp 199—201 °C. 1H-
NMR (Pyridine-d5) d: 0.75 (2H, m, H-3ꢈeq, H-5ꢈeq), 0.79 (3H, t, CH2–CH3),
0.87 (1H, m, H-4ꢈax), 1.07—1.12 (2H, q, CH2–CH3), 1.13—1.15 (2H, d, H-
2ꢈax, H-6ꢈax), 1.66 (2H, d, H-3ꢈax, H-5ꢈax,), 1.73 (2H, d, H-2ꢈeq, H-6ꢈeq), 2.17
(2H, d, H-3eq, H-5eq), 2.26 (1H, t, H-1ꢈax, Jꢁ11.6 Hz), 2.65 (2H, t, H-3ax, H-
5ax), 2.74 (2H, t, H-2ax, H-6ax), 2.85 (2H, d, H-2eq, H-6eq), 6.94 (1H, t, H-9ꢀ),
7.15 (1H, d, H-7ꢀ), 7.27 (1H, t, H-8ꢀ), 7.59 (1H, bs, NH), 8.21 (1H, d, H-
10ꢀ), 8.34 (1H, s, H-2ꢀ). MS m/z: 351 (Mꢇ), 280, 225, 213, 192, 155, 140.
Anal. Calcd for C21H29N5: C, 71.76; H, 8.32; N, 19.93. Found: C, 71.88; H,
7.95; N, 20.01.
NMR (Pyridine-d5) d: 0.78 (9H, s, tert-butyl), 0.80—0.89 (3H, m, H-3ꢈeq,
H-4ꢈax, H-5ꢈeq), 1.38 (2H, dd, H-2ꢈax, H-6ꢈax), 1.67 (2H, m, H-3ꢈax, H-5ꢈax),
1.80 (2H, d, H-2ꢈeq, H-6ꢈeq), 2.18 (2H, d, H-3eq, H-5eq), 2.23 (1H, t, H-1ꢈax,
Jꢁ11.2 Hz), 2.65 (2H, t, H-3ax, H-5ax), 2.77 (2H, t, H-2ax, H-6ax), 2.90 (2H,
d, H-2eq, H-6eq), 6.94 (1H, t, H-9ꢀ), 7.14 (1H, d, H-7ꢀ), 7.28 (1H, t, H-8ꢀ),
7.59 (1H, bs, NH), 8.21 (1H, d, H-10ꢀ), 8.35 (1H, s, H-2ꢀ). MS m/z: 379
(Mꢇ), 220, 213, 197, 168, 138, 184. Anal. Calcd for C23H33N5: C, 72.78; H,
8.77; N, 18.45. Found: C, 72.54; H, 8.40; N, 18.17.
1-Benzylspiro[piperidine-4,5ꢀ(6ꢀH)-[1,2,4]triazolo[1,5-c]quinazoline]
(4f) Compound 4f was obtained from 2f in 43% yield, white solids from
1
ethyl acetate, mp 158—160 °C. H-NMR (CDCl3) d: 2.00 (2H, d, H-3eq, H-
cis-1-(4-n-Propylcyclohexyl)-spiro[piperidine-4,5ꢀ(6ꢀH)-[1,2,4]tria-
zolo[1,5-c]quinazoline] (4c cis) Compound 4c cis was obtained from
5eq), 2.35 (2H, t, H-3ax, H-5ax), 2.55 (2H, t, H-2ax, H-6ax), 2.97 (2H, d, H-2eq,
H-6eq), 3.63 (2H, s, benzyl CH2), 4.61 (1H, bs, NH), 6.86 (1H, d, H-7ꢀ), 6.94
(1H, t, H-9ꢀ), 7.28—7.36 (6H, m, H-8ꢀ, benzyl protons), 7.90 (1H, d, H-10ꢀ),
7.97 (1H, s, H-2ꢀ). MS m/z: 331 (Mꢇ), 240, 213, 197, 185, 172. Anal. Calcd
for C20H21N5: C, 72.48; H, 6.39; N, 21.13. Found: C, 72.68; H, 6.23; N,
21.42.
1
2c cis in 38% yield, white solids from ethyl acetate, mp 130—131 °C. H-
NMR (Pyridine-d5) d: 0.85 (3H, t, CH2–CH2–CH3), 1.14—1.17 (2H, m,
CH2–CH2–CH3), 1.19–1.22 (2H, m, CH2–CH2–CH3), 1.29—1.33 (2H, m, H-
3ꢈax, H-5ꢈax), 1.35—1.39 (3H, m, H-2ꢈax, H-4ꢈ, H-6ꢈax), 1.39—1.41 (2H, m,
H-3ꢈeq, H-5ꢈeq), 1.53—1.57 (2H, m, H-2ꢈeq, H-6ꢈeq), 2.17 (2H, d, H-3eq, H-
5eq), 2.23 (1H, t, H-1ꢈax Jꢁ8.4 Hz), 2.59 (2H, t, H-3ax, H-5ax,), 2.65 (2H, t,
H-2ax, H-6ax), 2.90 (2H, d, H-2eq, H-6eq), 6.94 (1H, t, H-9ꢀ), 7.18 (1H, d, H-
7ꢀ), 7.28 (1H, t, H-8ꢀ), 7.52 (1H, bs, NH), 8.21 (1H, d, H-10ꢀ), 8.34 (1H, s,
H-2ꢀ). MS m/z: 365 (Mꢇ), 225, 213, 206, 197, 187, 154. Anal. Calcd for
C22H31N5: C, 72.29; H, 8.55; N, 19.16. Found: C, 72.51; H, 8.27; N, 19.31.
trans-1-(4-n-Propylcyclohexyl)-spiro[piperidine-4,5ꢀ(6ꢀH)-[1,2,4]tria-
zolo[1,5-c]quinazoline] (4c trans) Compound 4c trans was obtained from
2c trans in 37% yield, white solids from ethyl acetate, mp 172—174 °C. 1H-
NMR (Pyridine-d5) d: 0.77 (2H, d, H-3ꢈeq, H-5ꢈeq), 0.81 (3H, t, CH2–
CH2–CH3), 1.00—1.10 (3H, m, H-4ꢈax, CH2–CH2–CH3), 1.12—1.15 (2H, m,
H-2ꢈax, H-6ꢈax), 1.16—1.21 (2H, m, CH2–CH2–CH3), 1.66 (2H, m, H-3ꢈax,
H-5ꢈax,), 1.74 (2H, d, H-2ꢈeq, H-6ꢈeq), 2.17 (2H, d, H-3eq, H-5eq), 2.27 (1H, t,
H-1ꢈax, Jꢁ11.2 Hz), 2.65 (2H, t, H-3ax, H-5ax), 2.75 (2H, t, H-2ax, H-6ax),
2.85 (2H, d, H-2eq, H-6eq), 6.94 (1H, t, H-9ꢀ), 7.18 (1H, d, H-7ꢀ), 7.28 (1H, t,
H-8ꢀ), 7.59 (1H, bs, NH), 8.22 (1H, d, H-10ꢀ), 8.35 (1H, s, H-2ꢀ). MS m/z:
365 (Mꢇ), 225, 213, 206, 197, 187, 154. Anal. Calcd for C22H31N5: C, 72.29;
H, 8.55; N, 19.16. Found: C, 72.38; H, 8.36; N, 19.38.
1-Phenethylspiro[piperidine-4,5ꢀ(6ꢀH)-[1,2,4]triazolo[1,5-c]quinazo-
line] (4g) Compound 4g was obtained from 2g in 42% yield, white solids
1
from ethyl acetate, mp 134—136 °C. H-NMR (CDCl3) d: 2.07 (2H, d, H-
3eq, H-5eq), 2.38—2.55 (4H, m, H-2ax, H-3ax, H-5ax H-6ax), 2.70—2.88 (4H,
m, phenethyl CH2–CH2), 3.07 (2H, d, H-2eq, H-6eq), 4.64 (1H, bs, NH), 6.86
(1H, d, H-7ꢀ), 6.99 (1H, t, H-9ꢀ), 7.26—7.35 (6H, m, H-8ꢀ, phenyl protons),
7.90 (1H, d, H-10ꢀ), 7.97 (1H, s, H-2ꢀ). MS m/z: 345 (Mꢇ), 254, 225, 213,
197, 186. Anal. Calcd for C21H23N5: C, 73.01; H, 6.71; N, 20.28. Found: C,
73.28; H, 6.50; N, 20.08.
1-(1-Adamantyl)-spiro[piperidine-4,5ꢀ(6ꢀH)-[1,2,4]triazolo[1,5-
c]quinazoline] (4h) Compound 4h was obtained from 2h in 39% yield,
1
white solids from ethyl acetate, mp 260—264 °C (dec.). H-NMR (DMSO-
d6) d: 1.55—1.63 (6H, dd, H-2ꢈ, H-8ꢈ, H-9ꢈ), 1.68 (6H, bs, H-4ꢈ, H-6ꢈ, H-
10ꢈ), 1.92 (2H, d, H-3eq, H-5eq, Jꢁ12.8 Hz), 2.05 (3H, bs, H-3ꢈeq, H-5ꢈeq, H-
7ꢈeq), 2.17 (2H, t, H-3ax, H-5ax, Jꢁ10.8 Hz), 2.62 (2H, t, H-2ax, H-6ax,
Jꢁ10.8 Hz), 2.96 (2H, d, H-2eq, H-6eq), 6.82 (1H, t, H-9ꢀ), 7.00 (1H, bs,
NH), 7.05 (1H, d, H-7ꢀ), 7.24 (1H, t, H-8ꢀ), 7.65 (1H, d, H-10ꢀ), 7.99 (1H, s,
H-2ꢀ). MS m/z: 375 (Mꢇ), 240, 216, 164, 135. Anal. Calcd for C23H29N5: C,
73.56; H, 7.79; N, 18.65. Found: C, 73.23; H, 8.07; N, 18.44.
1-(5H-10,11-Dihydrodibenzo[a,d]cyclohepten-5-yl)-spiro[piperidine-
4,5ꢀ(6ꢀH)-[1,2,4]triazolo[1,5-c]quinazoline] (4i) Compound 4i was ob-
tained from 2i in 37% yield, white solids from ethyl acetate, mp 129—
131 °C. 1H-NMR (DMSO-d6) d: 1.89 (2H, d, H-3eq, H-5eq, Jꢁ12.4 Hz), 2.18
(2H, t, H-3ax, H-5ax, Jꢁ13.2 Hz), 2.44 (2H, t, H-2ax, H-6ax, Jꢁ12.5 Hz), 2.56
(2H, d, H-2eq, H-6eq, Jgemꢁ12.0 Hz), 2.75—2.80 (2H, dd, H-10ꢈ, H-11ꢈ),
3.92—3.98 (2H, dd, H-10ꢈ, H-11ꢈ), 4.18 (1H, s, H-5ꢈ), 6.82 (1H, t, H-9ꢀ),
7.03—7.23 (10H, m, dibenzosuberyl aromatics, H-7ꢀ and NH), 7.24 (1H, t,
H-8ꢀ), 7.64 (1H, d, H-10ꢀ), 8.00 (1H, s, H-2ꢀ). MS m/z: 433 (Mꢇ), 242, 193,
115. Anal. Calcd for C28H27N5: C, 77.57; H, 6.28; N, 16.16. Found: C,
77.46; H, 5.92; N, 16.03.
cis-1-(4-iso-Propylcyclohexyl)-spiro[piperidine-4,5ꢀ(6ꢀH)-[1,2,4]tria-
zolo[1,5-c]quinazoline] (4d cis) Compound 4d cis was obtained from
1
2d cis in 70% yield, white solids from ethyl acetate, mp 180—182 °C. H-
NMR (Pyridine-d5) d: 0.84 (6H, d, iso-propyl CH3), 0.98 (1H, m, H-4ꢈ),
1.24—1.34 (4H, m, H-2ꢈax, H-6ꢈax, H-3ꢈeq, H-5ꢈeq), 1.44 (1H, m, iso-propyl
CH). 1.50 (2H, m, H-3ꢈax, H-5ꢈax), 1.64 (2H, m, H-2ꢈeq, H-6ꢈeq), 2.17 (2H, d,
H-3eq, H-5eq), 2.24 (1H, t, H-1ꢈeq Jꢁ4.8 Hz), 2.54 (2H, t, H-3ax, H-5ax,), 2.65
(2H, t, H-2ax, H-6ax), 2.92 (2H, d, H-2eq, H-6eq), 6.95 (1H, t, H-9ꢀ), 7.16 (1H,
d, H-7ꢀ), 7.29 (1H, t, H-8ꢀ), 7.49 (1H, s, NH), 8.21 (1H, d, H-10ꢀ), 8.34 (1H,
s, H-2ꢀ). MS m/z: 365 (Mꢇ), 280, 252, 225, 213, 206, 197, 184, 169, 154.
Anal. Calcd for C22H31N5: C, 72.29; H, 8.55; N, 19.16. Found: C, 71.98; H,
8.79; N, 19.04.
trans-1-(4-iso-Propylcyclohexyl)-spiro[piperidine-4,5ꢀ(6ꢀH)-[1,2,4]tri-
azolo[1,5-c]quinazoline] (4d trans) Compound 4d trans was obtained
from 2d trans in 68% yield, white solids from ethyl acetate, mp 200—
202 °C. 1H-NMR (Pyridine-d5) d: 0.78 (6H, d, iso-propyl CH3), 0.84 (3H, m,
H-3ꢈeq, H-4ꢈax, H-5ꢈeq), 1.13 (2H, q, H-2ꢈax, H-6ꢈax), 1.28 (1H, m, iso-propyl
CH), 1.61 (2H, d, H-3ꢈax, H-5ꢈax), 1.77 (2H, d, H-2ꢈeq, H-6ꢈeq), 2.17 (2H, d,
H-3eq, H-5eq), 2.24 (1H, t, H-1ꢈax, Jꢁ12.0 Hz), 2.66 (2H, t, H-3ax, H-5ax),
2.76 (2H, t, H-2ax, H-6ax), 2.87 (2H, d, H-2eq, H-6eq), 6.94 (1H, t, H-9ꢀ), 7.14
(1H, d, H-7ꢀ), 7.28 (1H, t, H-8ꢀ), 7.59 (1H, bs, NH), 8.21 (1H, d, H-10ꢀ),
8.34 (1H, s, H-2ꢀ). MS m/z: 365 (Mꢇ), 280, 252, 225, 213, 206, 197, 184,
154, 138. Anal. Calcd for C22H31N5: C, 72.29; H, 8.55; N, 19.16. Found: C,
72.12; H, 8.23; N, 18.95.
General Procedure for the Preparation of the 1ꢀ-Methyl-spiro[piperi-
dine-4,2ꢀ(1ꢀH)-quinazolin]-4ꢀ(3ꢀH)-ones 3j—r A solution of the appro-
priate piperidone
0.01 mol) in acetic acid (14 ml) with two drops of sulfuric acid, was refluxed
for 30 min; then the mixture was cooled, diluted with water, alkalinized with
8% aqueous sodium hydroxide and repeatedly extracted with ethyl acetate.
The organic phase was then dried over sodium sulfate, evaporated in vacuo
and crystallized from the appropriate solvent.
2
(0.01 mol) and 2-methylaminobenzamide34) (1.5 g,
cis-1ꢀ-Methyl-1-(4-methylcyclohexyl)-spiro[piperidine-4,2ꢀ(1ꢀH)-
quinazolin]-4ꢀ(3ꢀH)-one (3j cis) Compound 3j cis was obtained from
1
2a cis in 29% yield, white solids from ethyl acetate, mp 183—186 °C. H-
NMR (Pyridine-d5) d: 0.86 (3H, d, 4ꢈ-CH3), 8.49 (1H, s, NH), 1.39 (7H, m,
H-3ꢈ, H-5ꢈ, H-2ꢈax, H-6ꢈax, H-4ꢈ), 1.60 (2H, m, H-2ꢈeq, H-6ꢈeq, Jꢁ8.1 Hz),
1.90 (2H, d, H-3eq, H-5eq, Jgemꢁ12.8 Hz), 2.03 (2H, t, H-3ax, H-5ax, Jꢁ
12.8 Hz), 2.17 (1H, t, H-1ꢈax, Jꢁ6.9 Hz), 2.53 (2H, t, H-2ax, H-6ax, Jꢁ
11.4 Hz), 2.74 (3H, s, N–CH3), 2.80 (2H, d, H-2eq, H-6eq, Jgemꢁ11.6 Hz),
6.85 (1H, d, H-8ꢀ, Jorthoꢁ8.1 Hz), 6.95 (1H, t, H-6ꢀ, Jorthoꢁ7.4 Hz), 7.43 (1H,
t, H-7ꢀ, Jorthoꢁ7.4 Hz), 8.39 (1H, d, H-5ꢀ, Jorthoꢁ7.6 Hz). MS m/z: 327 (Mꢇ),
310, 270, 242, 231, 203, 187, 175, 161, 153, 140, 134, 125. Anal. Calcd for
C20H29N3O: C, 73.35; H, 8.93; N, 12.83. Found: C, 73.04; H, 9.18; N, 12.65.
trans-1ꢀ-Methyl-1-(4-methylcyclohexyl)-spiro[piperidine-4,2ꢀ(1ꢀH)-
quinazolin]-4ꢀ(3ꢀH)-one (3j trans) Compound 3j trans was obtained from
2a trans in 29% yield, white solids from ethyl acetate, mp 219—221 °C. 1H-
NMR (Pyridine-d5) d: 0.78 (3H, d, 4ꢈ-CH3), 0.83 (2H, d, H-3ꢈeq, H-5ꢈeq,
cis-1-(4-tert-Butylcyclohexyl)-spiro[piperidine-4,5ꢀ(6ꢀH)-[1,2,4]tria-
zolo[1,5-c]quinazoline] (4e cis) Compound 4e cis was obtained from
1
2e cis in 40% yield, white solids from ethyl acetate, mp 150—152 °C. H-
NMR (Pyridine-d5) d: 0.80 (9H, s, tert-butyl), 0.97 (1H, t, H-4ꢈax,
Jꢁ8.4 Hz), 1.21 (2H, t, H-3ꢈax, H-5ꢈax), 1.25—1.39 (4H, m, H-2ꢈax, H-3ꢈeq,
H-5ꢈeq, H-6ꢈax), 1.94 (2H, d, H-2ꢈeq, H-6ꢈeq), 2.16—2.18 (3H, m, H-3eq, H-
5eq, H-1ꢈeq), 2.46 (2H, t, H-3ax, H-5ax), 2.62 (2H, t, H-2ax, H-6ax), 2.98 (2H, d,
H-2eq, H-6eq), 6.94 (1H, t, H-9ꢀ), 7.16 (1H, d, H-7ꢀ), 7.28 (1H, t, H-8ꢀ), 7.50
(1H, bs, NH), 8.21 (1H, d, H-10ꢀ), 8.33 (1H, s, H-2ꢀ). MS m/z: 379 (Mꢇ),
328, 297, 220, 213, 197, 184. Anal. Calcd for C23H33N5: C, 72.78; H, 8.77;
N, 18.45. Found: C, 72.56; H, 8.93; N, 18.19.
trans-1-(4-tert-Butylcyclohexyl)-spiro[piperidine-4,5ꢀ(6ꢀH)-[1,2,4]tria-
zolo[1,5-c]quinazoline] (4e trans) Compound 4e trans was obtained from
2e trans in 40% yield, white solids from ethyl acetate, mp 208—210 °C. 1H-
Jgemꢁ12.1 Hz), 1.12 (1H, um, H-4ꢈax), 1.19 (2H, q, H-2ꢈax, H-6ꢈax, Jꢁ
12.3 Hz), 1.60 (2H, d, H-3ꢈax, H-5ꢈax, Jgemꢁ11.9 Hz), 1.73 (2H, d, H-2ꢈeq, H-

620
Vol. 54, No. 5
6ꢈeq, Jgemꢁ11.4 Hz), 1.91 (2H, d, H-3eq, H-5eq, Jgemꢁ12.0 Hz), 2.02 (2H, dt,
H-3ax, H-5ax, Jꢁ12.5 Hz, Jꢁ5.1 Hz), 2.23 (1H, t, H-1ꢈax, Jdiaxꢁ11.5 Hz),
J
orthoꢁ7.4 Hz), 7.43 (1H, t, H-7ꢀ, Jorthoꢁ7.8 Hz), 8.39 (1H, d, H-5ꢀ, Jorthoꢁ
7.6 Hz), 8.50 (1H, s, NH). MS m/z: 355 (Mꢇ), 270, 242, 231, 221, 206, 203,
2.72 (4H, m, H-2, H-6), 2.75 (3H, s, N–CH3), 6.85 (1H, d, H-8ꢀ, Jorthoꢁ 187, 181, 175, 168, 161, 153, 138, 134, 124, 110. Anal. Calcd for
8.2 Hz), 6.96 (1H, t, H-6ꢀ, Jorthoꢁ7.4 Hz), 7.43 (1H, t, H-7ꢀ, Jorthoꢁ7.5 Hz),
C22H33N3O: C, 74.32; H, 9.36; N, 11.82. Found: C, 74.13; H, 9.70; N, 11.98.
trans-1ꢀ-Methyl-1-(4-iso-propylcyclohexyl)-spiro[piperidine-4,2ꢀ(1ꢀH)-
8.39 (1H, d, H-5ꢀ, Jorthoꢁ7.5 Hz), 8.49 (1H, s, NH). MS m/z: 327 (Mꢇ), 270,
242, 231, 203, 187, 175, 161, 153, 140, 134, 125. Anal. Calcd for quinazolin]-4ꢀ(3ꢀH)-one (3m trans) Compound 3m trans was obtained
C20H29N3O: C, 73.35; H, 8.93; N, 12.83. Found: C, 73.27; H, 9.15; N, 13.09.
cis-1-(4-Ethylcyclohexyl)-1ꢀ-methyl-spiro[piperidine-4,2ꢀ(1ꢀH)-quina-
zolin]-4ꢀ(3ꢀH)-one (3k cis) Compound 3k cis was obtained from 2b cis in
from 2d trans in 70% yield, white solids from ethyl acetate, mp 199—
201 °C. 1H-NMR (Pyridine-d5) d: 0.78 (6H, d, iso-propyl CH3), 0.85 (3H, m,
H-3ꢈeq, H-4ꢈax, H-5ꢈeq), 1.16 (2H, dd, H-2ꢈax, H-6ꢈax, Jgemꢁ11.4 Hz), 1.29
31% yield, white solids from ethyl acetate, mp 173—174 °C. 1H-NMR (Pyri- (1H, m, iso-propyl CH), 1.61 (2H, d, H-3ꢈax, H-5ꢈax, Jgemꢁ12.0 Hz), 1.80
dine-d5) d: 0.85 (3H, t, ethyl CH3), 1.21 (2H, qt, ethyl CH2), 1.40 (7H, m, H-
3ꢈ, H-5ꢈ, H-2ꢈax, H-6ꢈax, H-4ꢈ), 1.56 (2H, m, H-2ꢈeq, H-6ꢈeq, Jꢁ8.7 Hz), 1.89
(2H, d, H-2ꢈeq, H-6ꢈeq, Jgemꢁ11.3 Hz), 1.91 (2H, d, H-3eq, H-5eq, Jgemꢁ
11.6 Hz), 2.02 (2H, dt, H-3ax, H-5ax, Jgemꢁ11.8 Hz, Jdiaxꢁ10.6 Hz, Jax-eqꢁ
(2H, d, H-3eq, H-5eq, Jgemꢁ12.5 Hz), 2.02 (2H, dt, H-3ax, H-5ax, Jꢁ12.8 Hz, 5.5 Hz), 2.22 (1H, t, H-1ꢈax, Jdiaxꢁ11.6 Hz, Jax-eqꢁ3.0 Hz), 2.75 (7H, over-
Jꢁ4.1 Hz), 2.22 (1H, t, H-1ꢈax, Jꢁ7.8 Hz), 2.60 (2H, t, H-2ax, H-6ax, Jꢁ lapped s and m, H-2, H-6, N–CH3), 6.85 (1H, d, H-8ꢀ, Jorthoꢁ8.3 Hz), 6.96
11.6 Hz), 2.74 (3H, s, N–CH3), 2.79 (2H, d, H-2eq, H-6eq, Jgemꢁ11.8 Hz),
6.84 (1H, d, H-8ꢀ, Jorthoꢁ8.2 Hz), 6.95 (1H, t, H-6ꢀ, Jorthoꢁ7.4 Hz), 7.43 (1H,
t, H-7ꢀ, Jorthoꢁ7.3 Hz), 8.37 (1H, d, H-5ꢀ, Jorthoꢁ7.6 Hz), 8.65 (1H, s, NH).
(1H, t, H-6ꢀ, Jorthoꢁ7.4 Hz), 7.44 (1H, t, H-7ꢀ, Jorthoꢁ7.2 Hz), 8.38 (1H, d, H-
5ꢀ, Jorthoꢁ7.5 Hz), 8.54 (1H, s, NH). MS m/z: 355 (Mꢇ), 342, 270, 242, 231,
221, 206, 203, 187, 181, 175, 168, 161, 153, 138, 134, 124, 110. Anal. Calcd
MS m/z: 341 (Mꢇ), 270, 242, 231, 203, 192, 187, 175, 167, 161, 154, 140, for C22H33N3O: C, 74.32; H, 9.36; N, 11.82. Found: C, 74.49; H, 9.27; N,
134, 120, 110. Anal. Calcd for C21H31N3O: C, 73.86; H, 9.15; N, 12.31. 11.59.
Found: C, 74.02; H, 8.82; N, 12.45.
trans-1-(4-Ethylcyclohexyl)-1ꢀ-methyl-spiro[piperidine-4,2ꢀ(1ꢀH)- quinazolin]-4ꢀ(3ꢀH)-one (3n cis) Compound 3n cis was obtained from
quinazolin]-4ꢀ(3ꢀH)-one (3k trans) Compound 3k trans was obtained
2e cis in 32% yield, white solids from methanol, mp 190—192 °C. 1H-NMR
cis-1-(4-tert-Butylcyclohexyl)-1ꢀ-methyl-spiro[piperidine-4,2ꢀ(1ꢀH)-
from 2b trans in 31% yield, white solids from ethyl acetate, mp 200— (Pyridine-d5) d: 0.83 (9H, s, tert-butyl), 0.99 (1H, m, H-4ꢈax, Jdiaxꢁ13.4 Hz,
202 °C. 1H-NMR (Pyridine-d5) d: 0.77 (2H, d, H-3ꢈeq, H-5ꢈeq, Jgemꢁ
11.6 Hz), 0.81 (3H, t, ethyl CH3), 0.89 (1H, bm, H-4ꢈax), 1.10 (2H, qt, ethyl
J
J
diaxꢁ11.3 Hz, Jax-eqꢁ4.1 Hz), 1.24 (2H, t, H-2ꢈax, H-6ꢈax, Jgemꢁ13.8 Hz,
diaxꢁ13.3 Hz, Jax-eqꢁ2.5 Hz), 1.35 (4H, m, H-3ꢈ, H-5ꢈ), 1.92 (2H, d, H-3eq,
CH2), 1.18 (2H, q, H-2ꢈax, H-6ꢈax, Jꢁ11.7 Hz), 1.67 (2H, d, H-3ꢈax, H-5ꢈax, H-5eq, Jgemꢁ12.3 Hz), 1.97 (2H, d, H-2ꢈeq, H-6ꢈeq, Jgemꢁ14.0 Hz, Jeq-axꢁ
J
gemꢁ11.9 Hz), 1.77 (2H, d, H-2ꢈeq, H-6ꢈeq, Jgemꢁ11.3 Hz), 1.91 (2H, d, H-
2.2 Hz), 2.02 (2H, t, H-3ax, H-5ax, Jgemꢁ12.2 Hz, Jdiaxꢁ12.2 Hz, Jax-eqꢁ
3.8 Hz), 2.13 (1H, sh m, H-1ꢈeq, Jꢁ2.7 Hz), 2.38 (2H, t, H-2ax, H-6ax, Jgemꢁ
3eq, H-5eq, Jgemꢁ11.9 Hz), 2.03 (2H, bt, H-3ax, H-5ax, Jgem, Jdiaxꢁ11.8 Hz, Jax-
eqꢁ5.2 Hz), 2.24 (1H, t, H-1ꢈax, Jdiaxꢁ11.6 Hz), 2.76 (7H, overlapped s and 11.5 Hz, Jdiaxꢁ11.4 Hz), 2.71 (3H, s, N–CH3), 2.88 (2H, d, H-2eq, H-6eq,
m, H-2, H-6, N–CH3), 6.85 (1H, d, H-8ꢀ, Jorthoꢁ8.3 Hz), 6.96 (1H, t, H-6ꢀ,
Jgemꢁ11.5 Hz), 6.86 (1H, d, H-8ꢀ, Jorthoꢁ7.4 Hz), 6.96 (1H, t, H-6ꢀ, Jorthoꢁ
J
orthoꢁ7.4 Hz), 7.43 (1H, t, H-7ꢀ, Jorthoꢁ8.0 Hz), 8.38 (1H, d, H-5ꢀ, Jorthoꢁ 7.4 Hz), 7.43 (1H, t, H-7ꢀ, Jorthoꢁ7.2 Hz, Jmetaꢁ1.7 Hz), 8.39 (1H, d, H-5ꢀ,
7.5 Hz), 8.52 (1H, s, NH). MS m/z: 341 (Mꢇ), 270, 242, 230, 203, 192, 187,
J
orthoꢁ7.6 Hz, Jmetaꢁ1.6 Hz), 8.48 (1H, s, NH). MS m/z: 369 (Mꢇ), 354, 270,
175, 167, 160, 154, 140, 134, 110. Anal. Calcd for C21H31N3O: C, 73.86; H, 242, 231, 220, 202, 188, 175, 167, 161, 152, 138, 134, 120, 110. Anal. Calcd
9.15; N, 12.31. Found: C, 74.16; H, 9.31; N, 12.56.
cis-1ꢀ-Methyl-1-(4-n-propylcyclohexyl)-spiro[piperidine-4,2ꢀ(1ꢀH)-
for C23H35N3O: C, 74.75; H, 9.55; N, 11.37. Found: C, 74.99; H, 9.24; N,
11.23.
quinazolin]-4ꢀ(3ꢀH)-one (3l cis) Compound 3l cis was obtained from
2c cis in 31% yield, white solids from ethyl acetate, mp 140—141 °C. H- quinazolin]-4ꢀ(3ꢀH)-one (3n trans) Compound 3n trans was obtained
trans-1-(4-tert-Butylcyclohexyl)-1ꢀ-methyl-spiro[piperidine-4,2ꢀ(1ꢀH)-
1
NMR (Pyridine-d5) d: 0.85 (3H, t, n-propyl CH3), 1.19 (4H, m, H-2ꢈax, H-
from 2e trans in 32% yield, white solids from ethyl acetate, mp 253—
6ꢈax, n-propyl CH2), 1.40 (7H, m, H-3ꢈ, H-4ꢈ, H-5ꢈ, n-propyl 4ꢈ-CH2), 1.57 255 °C. 1H-NMR (Pyridine-d5) d: 0.78 (9H, s, tert-butyl), 0.83 (1H, t, H-
(2H, at, H-2ꢈeq, H-6ꢈeq, Jꢁ8.6 Hz), 1.91 (2H, d, H-3eq, H-5eq, Jgemꢁ12.3 Hz),
2.04 (2H, t, H-3ax, H-5ax, Jgemꢁ12.7 Hz, Jdiaxꢁ11.4 Hz, Jax-eqꢁ3.4 Hz), 2.20
(1H, t, H-1ꢈax, Jꢁ6.7 Hz), 2.54 (2H, t, H-2ax, H-6ax, Jgemꢁ11.2 Hz), 2.75
(3H, s, N–CH3), 2.81 (2H, bd, H-2eq, H-6eq, Jgemꢁ11.8 Hz), 6.86 (1H, d, H-
4ꢈax, Jdiaxꢁ11.9 Hz, Jax-eqꢁ2.6, 2.2 Hz), 0.86 (2H, q, H-3ꢈeq, H-5ꢈeq, Jgemꢁ
12.0 Hz), 1.15 (2H, q, H-2ꢈax, H-6ꢈax, Jgemꢁ12.1 Hz, Jdiaxꢁ11.9 Hz, Jax-eqꢁ
2.1 Hz), 1.67 (2H, d, H-3ꢈax, H-5ꢈax, Jgemꢁ11.5 Hz), 1.83 (2H, d, H-2ꢈeq, H-
6ꢈeq, Jgemꢁ12.1 Hz), 1.93 (2H, d, H-3eq, H-5eq, Jgemꢁ12.0 Hz), 2.04 (2H, bt,
8ꢀ, Jorthoꢁ8.1 Hz), 6.96 (1H, t, H-6ꢀ, Jorthoꢁ7.4 Hz), 7.43 (1H, t, H-7ꢀ, H-3ax, H-5ax, Jgemꢁ2.0 Hz, Jdiaxꢁ9.9 Hz), 2.21 (1H, t, H-1ꢈax, Jdiaxꢁ11.5 Hz),
J
orthoꢁ7.8 Hz), 8.39 (1H, d, H-5ꢀ, Jorthoꢁ7.6 Hz), 8.45 (1H, s, NH). MS m/z: 2.76 (3H, s, N–CH3), 2.73—2.80 (4H, m, H-2, H-6), 6.85 (1H, d, H-8ꢀ,
355 (Mꢇ), 270, 242, 231, 221, 206, 203, 187, 181, 175, 168, 161, 153, 134,
124, 110. Anal. Calcd for C22H33N3O: C, 74.32; H, 9.36; N, 11.82. Found: C,
74.55; H, 9.19; N, 12.13.
Jorthoꢁ7.7 Hz), 6.96 (1H, t, H-6ꢀ,
Jorthoꢁ7.4 Hz), 7.43 (1H, t, H-7ꢀ,
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orthoꢁ7.4 Hz, Jmetaꢁ1.6 Hz), 8.39 (1H, d, H-5ꢀ, Jorthoꢁ7.6 Hz, Jmetaꢁ1.6 Hz).
MS m/z: 369 (Mꢇ), 354, 270, 242, 231, 220, 202, 187, 175, 167, 161, 152,
trans-1ꢀ-Methyl-1-(4-n-propylcyclohexyl)-spiro[piperidine-4,2ꢀ(1ꢀH)- 138, 134, 119, 110. Anal. Calcd for C23H35N3O: C, 74.75; H, 9.55; N, 11.37.
quinazolin]-4ꢀ(3ꢀH)-one (3l trans) Compound 3l trans was obtained from
2c trans in 31% yield, white solids from ethyl acetate, mp 206—208 °C. 1H-
NMR (Pyridine-d5) d: 0.78 (2H, d, H-3ꢈeq, H-5ꢈeq, Jgemꢁ11.7 Hz), 0.84 (3H,
Found: C, 74.40; H, 9.25; N, 11.18.
1-Benzyl-1ꢀ-methyl-spiro[piperidine-4,2ꢀ(1ꢀH)-quinazolin]-4ꢀ(3ꢀH)-
one (3o) Compound 3o was obtained from 2f in 24% yield, white solids
t, n-propyl CH3), 1.05 (3H, m, H-4ꢈ, n-propyl CH2), 1.17 (2H, t, H-2ꢈax, H- from ethyl acetate, mp 158—160 °C (lit.35) 158—159 °C from methanol).
6ꢈax, Jgemꢁ11.4 Hz), 1.22 (2H, qt, n-propyl 4ꢈ-CH2), 1.68 (2H, m, H-3ꢈax, H- 1H-NMR (DMSO-d6) d: 1.67 (2H, d, H-3eq, H-5eq, Jgemꢁ12.5 Hz), 1.92 (2H,
5ꢈax, Jgemꢁ12.0 Hz), 1.78 (2H, d, H-2ꢈeq, H-6ꢈeq, Jgemꢁ11.3 Hz), 1.91 (2H, d, t, H-3ax, H-5ax, Jꢁ12.4 Hz), 2.39 (2H, t, H-2ax, H-6ax, Jꢁ11.2 Hz), 2.59 (2H,
H-3eq, H-5eq, Jgemꢁ12.1 Hz), 2.03 (2H, dt, H-3ax, H-5ax, Jgemꢁ12.8 Hz, Jdiaxꢁ d, H-2eq, H-6eq, Jgemꢁ11.8 Hz), 2.79 (3H, s, N–CH3), 3.47 (2H, s, benzyl
10.6 Hz, Jax-eqꢁ5.5 Hz), 2.25 (1H, t, H-1ꢈax, Jdiaxꢁ11.6 Hz, Jax-eqꢁ3.0 Hz),
2.75 (7H, overlapped s and m, H-2, H-6, N–CH3), 6.85 (1H, d, H-8ꢀ, Jorthoꢁ 7.28 (5H, sh m, benzyl aromatics), 7.39 (1H, dt, H-7ꢀ, Jorthoꢁ7.3 Hz, Jmetaꢁ
8.3 Hz), 6.96 (1H, t, H-6ꢀ, Jorthoꢁ7.4 Hz), 7.44 (1H, t, H-7ꢀ, Jorthoꢁ7.2 Hz), 1.6 Hz), 7.69 (1H, dd, H-5ꢀ, Jorthoꢁ7.6 Hz, Jmetaꢁ1.6 Hz), 8.02 (1H, s, NH).
8.39 (1H, d, H-5ꢀ, Jorthoꢁ7.5 Hz), 8.51 (1H, s, NH). MS m/z: 355 (Mꢇ), 340, MS m/z: 321 (Mꢇ), 308, 230, 203, 187, 175, 161, 146, 134, 118, 91. Anal.
270, 242, 231, 221, 206, 203, 187, 181, 175, 168, 161, 153, 134, 124, 110. Calcd for C20H23N3O: C, 74.73; H, 7.21; N, 13.08. Found: C, 74.48; H, 7.50;
Anal. Calcd for C22H33N3O: C, 74.32; H, 9.36; N, 11.82. Found: C, 74.21; H, N, 13.41.
CH2), 6.82 (1H, t, H-6ꢀ, Jorthoꢁ7.4 Hz), 6.87 (1H, d, H-8ꢀ, Jorthoꢁ8.1 Hz),
8.99; N, 12.07.
1ꢀ-Methyl-1-phenethyl-spiro[piperidine-4,2ꢀ(1ꢀH)-quinazolin]-
cis-1ꢀ-Methyl-1-(4-iso-propylcyclohexyl)-spiro[piperidine-4,2ꢀ(1ꢀH)- 4ꢀ(3ꢀH)-one (3p) Compound 3p was obtained from 2g in 30% yield, white
quinazolin]-4ꢀ(3ꢀH)-one (3m cis) Compound 3m cis was obtained from solids from ethanol, mp 163—165 °C.1H-NMR (DMSO-d6) d: 1.69 (2H, d,
1
2d cis in 50% yield, white solids from ethyl acetate, mp 142—144 °C. H- H-3eq, H-5eq, Jgemꢁ12.3 Hz), 1.91 (2H, t, H-3ax, H-5ax, Jꢁ10.5 Hz), 2.43
NMR (Pyridine-d5) d: 0.83 (6H, d, iso-propyl CH3), 1.00 (1H, bm, H-4ꢈ), (2H, t, H-2ax, H-6ax, Jꢁ11.0 Hz), 2.55 (2H, d partially under solvent signal,
1.27 (2H, d. H-3ꢈeq, H-5ꢈeq), 1.35 (1H, t, H-2ꢈax, H-6ꢈax,), 1.44 (1H, m, iso- H-2eq, H-6eq), 2.67 (4H, m, phenethyl CH2–CH2), 2.79 (3H, s, NCH3), 6.83
propyl CH), 1.51 (2H, t, H-3ꢈax, H-5ꢈax), 1.66 (2H, d, H-2ꢈeq, H-6ꢈeq), 1.92 (1H, t, H-6ꢀ, Jorthoꢁ7.4 Hz), 6.88 (1H, d, H-8ꢀ, Jorthoꢁ7.8 Hz), 7.22 (5H, m,
(2H, d, H-3eq, H-5eq, Jgemꢁ12.4 Hz), 2.03 (2H, t, H-3ax, H-5ax, Jgemꢁ12.7 Hz, phenethyl aromatics), 7.36 (1H, t, H-7ꢀ, Jorthoꢁ7.3 Hz), 7.70 (1H, d, H-5ꢀ,
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diaxꢁ11.4 Hz, Jax-eqꢁ3.4 Hz), 2.19 (1H, sh m, H-1ꢈeq, Jꢁ2.7 Hz), 2.52 (2H,
t, H-2ax, H-6ax, Jgemꢁ11.2 Hz), 2.74 (3H, s, N–CH3), 2.83 (2H, d, H-2eq, H-
6eq, Jgemꢁ11.8 Hz), 6.86 (1H, d, H-8ꢀ, Jorthoꢁ8.1 Hz), 6.96 (1H, t, H-6ꢀ, 12.53. Found: C, 75.40; H, 7.16; N, 12.21.
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orthoꢁ7.4 Hz), 8.03 (1H, s, NH). MS m/z: 335 (Mꢇ), 244, 231, 216, 203,
187, 174, 160, 134, 91. Anal. Calcd for C21H25N3O: C, 75.19; H, 7.51; N,

May 2006
621
1-(1-Adamantyl)-1ꢀ-methyl-spiro[piperidine-4,2ꢀ(1ꢀH)-quinazolin]- NMR (DMSO-d6) d: 0.82 (9H, s, tert-butyl), 0.93 (3H, m, H-3ꢈax, H-4ꢈax, H-
4ꢀ(3ꢀH)-one (3q) Compound 3q was obtained from 2h in 38% yield, white 5ꢈax), 1.18 (2H, m, H-2ꢈax, H-6ꢈax), 1.86 (8H, m, H-3, H-5, H-2ꢈeq, H-3ꢈeq, H-
solids from ethyl acetate, mp 255—257 °C. 1H-NMR (DMSO-d6) d: 1.56 5ꢈeq, H-6ꢈeq), 2.24 (1H, t, H-1ꢈax), 2.65 (4H, m, H-2, H-6), 4.61 (2H, s, 1ꢀ-
(3H, d, H-2ꢈax, H-8ꢈax, H-9ꢈax, Jgemꢁ12.1 Hz), 1.60 (3H, d, H-2ꢈeq, H-8ꢈeq, H-
benzyl CH2), 6.68 (1H, d, H-8ꢀ, Jorthoꢁ8.2 Hz), 6.77 (1H, t, H-6ꢀ, Jorthoꢁ
9ꢈeq, Jgemꢁ12.1 Hz), 1.64 (6H, bs, H-4ꢈ, H-6ꢈ, H-10ꢈ), 1.68 (2H, d, H-3eq, H- 7.3 Hz), 7.29 (1H, t, H-7ꢀ, Jorthoꢁ7.4 Hz), 7.32 (5H, m, benzyl group aromat-
5eq, Jꢁ12.0 Hz), 1.80 (2H, t, H-3ax, H-5ax, Jꢁ11.7 Hz), 2.03 (3H, bs, H-3ꢈeq,
H-5ꢈeq, H-7ꢈeq), 2.45 (2H, t, H-2ax, H-6ax, Jꢁ11.0 Hz), 2.54 (2H, d partially
under solvent signal, H-2eq, H-6eq), 2.79 (3H, s, NCH3), 6.81 (1H, t, H-6ꢀ,
ics), 7.73 (1H, d, H-5ꢀ, Jorthoꢁ7.5 Hz), 8.12 (1H, s, NH). MS m/z: 445 (Mꢇ),
354, 326, 299, 279, 263, 250, 235, 220, 182, 161, 132, 91. Anal. Calcd for
C29H39N3O: C, 78.16; H, 8.82; N, 9.43. Found: C, 77.95; H, 8.93; N, 9.34.
1,1ꢀ-Dibenzylspiro[piperidine-4,2ꢀ(1ꢀH)-quinazolin]-4ꢀ(3ꢀH)-one (3u)
Compound 3u was obtained from 2f in 12% yield, white solids from ethyl
Jorthoꢁ7.4 Hz), 6.86 (1H, d, H-8ꢀ, Jorthoꢁ7.8 Hz), 7.39 (1H, t, H-7ꢀ,
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orthoꢁ7.4 Hz), 7.68 (1H, s, H-5ꢀ, Jorthoꢁ7.5 Hz), 7.98 (1H, s, NH). MS m/z:
365 (Mꢇ), 337, 230, 216, 202, 187, 178, 164, 135. Anal. Calcd for
acetate, mp 233—235 °C. H-NMR (CDCl3) d: 1.98 (4H, sh m, H-3, H-5),
2.26 (2H, m, H-2ax, H-6ax), 2.77 (2H, bd, H-2eq, H-6eq, Jgemꢁ11.7 Hz), 3.46
1
C23H31N3O: C, 75.58; H, 8.55; N, 11.50. Found: C, 75.48; H, 8.32; N, 11.72.
1-(5H-10,11-Dihydrodibenzo[a,d]cyclohepten-5-yl)-1ꢀ-methyl- (2H, s, 1-benzyl CH2), 4.52 (2H, s, 1ꢀ-benzyl CH2), 6.53 (1H, d, H-8ꢀ,
spiro[piperidine-4,2ꢀ(1ꢀH)-quinazolin]-4ꢀ(3ꢀH)-one (3r) Compound 3r orthoꢁ8.4 Hz), 6.62 (1H, bs, NH), 6.73 (1H, t, H-6ꢀ, Jorthoꢁ7.3 Hz), 7.24
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was obtained from 2i in 34% yield, white solids from ethyl acetate, mp (11H, m, overlapped benzyl group aromatics and H-7ꢀ), 7.90 (1H, d, H-5ꢀ,
261—263 °C. 1H-NMR (DMSO-d6) d: 1.62 (2H, d, H-3eq, H-5eq, Jgemꢁ
12.6 Hz), 1.84 (2H, m, H-3ax, H-5ax), 2.36 (4H, m, H-2, H-6), 2.77 (5H,
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orthoꢁ7.6 Hz). MS m/z: 397 (Mꢇ), 306, 279, 263, 251, 210, 187, 172, 160,
146, 134, 118, 91. Anal. Calcd for C26H27N3O: C, 78.56; H, 6.85; N, 10.57.
overlapped s and m, N–CH3, H-10ꢈ, H-11ꢈ), 3.93 (2H, m, H-10ꢈ, H-11ꢈ), Found: C, 78.69; H, 6.48; N, 10.36.
4.10 (1H, s, H-5ꢈ), 6.82 (1H, t, H-6ꢀ, Jorthoꢁ7.3 Hz), 6.87 (1H, d, H-8ꢀ, General Procedure for the Preparation of the 1ꢀ-Methyl-spiro[piperi-
orthoꢁ7.9 Hz), 7.13 (8H, m, dibenzosuberyl aromatics), 7.38 (1H, t, H-7ꢀ, dine-4,2ꢀ(1ꢀH)-quinazolin]-4ꢀ(3ꢀH)-ones 4m, n To stirred and ice-
J
J
a
orthoꢁ7.4 Hz, Jmetaꢁ1.7 Hz), 7.68 (1H, dd, H-5ꢀ, Jorthoꢁ7.6 Hz, Jmetaꢁ1.6
cooled solution of the appropriate compound 4 (0.0013 mol) in formic acid
Hz), 7.94 (1H, s, NH). MS m/z: 423 (Mꢇ), 232, 203, 193, 187, 178, 165, (15 ml), sodium borohydride (13.2 mmol) was very slowly and carefully
134, 115. Anal. Calcd for C28H29N3O: C, 79.40; H, 6.90; N, 9.92. Found: C, added in small portions; cooling and stirring were continued until compound
79.12; H, 7.16; N, 9.73.
4 disappeared as revealed by TLC. The mixture was poured in ice, made al-
General Procedure for the Preparation of the 1ꢀ-Benzylspiro[piperi- kaline by aqueous sodium hydroxide and extracted with ethyl acetate. The
dine-4,2ꢀ(1ꢀH)-quinazolin]-4ꢀ(3ꢀH)-ones 3s—u A solution of the appro-
organic phase dried on sodium sulfate was evaporated and the obtained
priate piperidone (0.01 mol) and 2-benzylaminobenzamide36) (2.3 g, 0.01 residue was chromatographed on aluminium oxide eluting by an ethyl ac-
mol) in acetic acid (20 ml) with two drops of sulfuric acid, was refluxed for etate/hexane 2 : 1 (v/v) mixture.
3 h; then the mixture was cooled, diluted with water, made alkaline with 8%
cis-1ꢀ-Methyl-1-(4-iso-propylcyclohexyl)-spiro[piperidine-4,5ꢀ(6ꢀH)-
aqueous sodium hydroxide and repeatedly extracted with ethyl acetate. The [1,2,4]triazolo[1,5-c]quinazoline] (4m cis) Compound 4m cis was ob-
organic phase was dried over sodium sulfate, evaporated in vacuo and the
residue crystallized from the appropriate solvent.
cis-1ꢀ-Benzyl-1-(4-iso-propylcyclohexyl)-spiro[piperidine-4,2ꢀ(1ꢀH)-
tained from 4d cis in 25% yield as pale yellow solids, mp 110—112 °C
1
(from ethyl ether). H-NMR (CDCl3) d: 0.83 (6H, d, iso-propyl CH3), 1.07
(1H, m, H-4ꢈax Jꢁ9.8 Hz), 1.31 (2H, dt, H-3ꢈeq, H-5ꢈeq), 1.40—1.70 (7H, m,
H-2ꢈ, H-3ꢈax, H-5ꢈax, H-6ꢈ, iso-propyl CH), 1.83 (2H, d, H-3eq, H-5eq), 1.99
quinazolin]-4ꢀ(3ꢀH)-one (3s cis) Compound 3s cis was obtained from
1
2d cis in 68% yield, white solids from ethyl acetate, mp 162—164 °C. H- (2H, t, H-3ax, H-5ax,), 2.20 (1H, t, H-1ꢈeq Jꢁ4.8 Hz), 2.72 (3H, s, NCH3),
NMR (DMSO-d6) d: 0.81 (6H, d, iso-propyl CH3), 1.04 (1H, m, H-4ꢈ), 1.28 2.79 (2H, t, H-2ax, H-6ax), 2.98 (2H, d, H-2eq, H-6eq), 7.25—7.41 (3H, m, H-
(2H, m, H-3ꢈeq, H-5ꢈeq), 1.36 (2H, t, H-2ꢈax, H-6ꢈax,), 1.49 (3H, m, H-3ꢈax, H- 7ꢀ, H-8ꢀ, H-9ꢀ), 7.98 (1H, s, H-2ꢀ), 8.31 (1H, d, H-10ꢀ). MS m/z: Anal. Calcd
5ꢈax, iso-propyl CH), 1.61 (2H, m, H-2eq, H-6eq), 1.85 (4H, bs, H-3, H-5),
2.22 (1H, sh m, H-1ꢈeq), 2.44 (2H, m, H-2ax, H-6ax), 2.71 (2H, d, H-2eq, H-
6eq), 4.59 (2H, s, 1ꢀ-benzyl CH2) 6.66 (1H, t, H-8ꢀ, Jorthoꢁ8.4 Hz), 6.75 (1H,
t, H-6ꢀ, Jorthoꢁ7.4 Hz), 7.27 (6H, m, overlapped benzyl group aromatics and
for C23H33N5: C, 72.78; H, 8.77; N, 18.45. Found: C, 72.98; H, 8.54; N,
18.37.
cis-1-(4-tert-Butylcyclohexyl)-6ꢀ-methyl-spiro[piperidine-4,5ꢀ(6ꢀH)-
[1,2,4]triazolo[1,5-c]quinazoline] (4n cis) Compound 4n cis was obtained
H-7ꢀ), 7.71 (1H, d, H-5ꢀ, Jorthoꢁ7.6 Hz), 8.03 (1H, s, NH). MS m/z: 431 from 4e cis in 30% yield as white solids, mp 143—145 °C (from ethyl ac-
(Mꢇ), 346, 312, 307, 285, 279, 263, 250, 221, 206, 180, 161, 132, 110. Anal. etate). 1H-NMR (CDCl3) d: 0.79 (9H, s, tert-butyl), 1.00 (1H, bt, H-4ꢈax),
Calcd for C28H37N3O: C, 77.91; H, 8.64; N, 9.74. Found: C, 78.03; H, 8.35; 1.22—2.06 (14H, m, H-6ax, H-3, H-5, H-1ꢈeq, H-2ꢈ, H-3ꢈ, H-5ꢈ, H-6ꢈ), 2.70
N, 9.91.
(3H, s, NCH3), 2.77 (1H, t, H-2ax), 3.00 (2H, d, H-2eq, H-6eq), 7.24—7.44
trans-1ꢀ-Benzyl-1-(4-iso-propylcyclohexyl)-spiro[piperidine-4,2ꢀ(1ꢀH)- (3H, m, H-7ꢀ, H-8ꢀ, H-9ꢀ), 7.99 (1H, s, H-2ꢀ), 8.32 (1H, d, H-10ꢀ). MS m/z:
quinazolin]-4ꢀ(3ꢀH)-one (3s trans) Compound 3s trans was obtained from 393 (Mꢇ), 223, 220, 208, 180, 171, 166, 124. Anal. Calcd for C24H35N5: C,
2d trans in 70% yield, white solids from ethyl acetate, mp 232—234 °C. 1H- 73.24; H, 8.97; N, 17.80. Found: C, 73.29; H, 8.65; N, 17.59.
NMR (DMSO-d6) d: 0.81 (6H, d, iso-propyl CH3), 0.93 (3H, m, H-3ꢈeq, H-
4ꢈax, H-5ꢈeq), 1.15 (2H, dd, H-2ꢈax, H-6ꢈax, Jgemꢁ11.4 Hz), 1.38 (1H, m, iso- (1.0 g, 0.026 mol) was portionwise added to a suspension of [1,2,4]tria-
propyl CH), 1.55 (2H, m, H-3ꢈax, H-5ꢈax, Jgemꢁ12.0 Hz), 1.78 (2H, d, H-2ꢈeq,
zolo[1,5-c]quinazoline25) (0.5 g, 0.003 mol) in methanol (25 ml) and the mix-
5,6-Dihydro-[1,2,4]triazolo[1,5-c]quinazoline Sodium borohydride
H-6ꢈeq, Jgemꢁ11.3 Hz), 1.84 (4H, bs, H-3, H-5), 2.20 (1H, t, H-1ꢈax, Jdiaxꢁ ture left at room temperature under stirring for 2 h; then the solvent was re-
11.6 Hz, Jax-eqꢁ3.0 Hz), 2.60 (4H, m, H-2, H-6), 4.61 (2H, s, 1ꢀ-benzyl moved in vacuo and the residue suspended in water and extracted with chlo-
CH2), 6.66 (1H, d, H-8ꢀ, Jorthoꢁ8.2 Hz), 6.76 (1H, t, H-6ꢀ, Jorthoꢁ7.3 Hz),
7.27 (1H, t, H-7ꢀ, Jorthoꢁ7.4 Hz), 7.32 (5H, m, benzyl group aromatics), 7.71
roform; the organic layer was then dried with sodium sulfate and the solvent
evaporated in vacuo giving the product in 75% yield, colorless solid from
1
(1H, d, H-5ꢀ, Jorthoꢁ7.5 Hz), 8.04 (1H, s, NH). MS m/z: 431 (Mꢇ), 340, 312, benzene, mp 200—201 °C. H-NMR (DMSO-d6) d: 5.54 (2H, d, H-5), 6.81
307, 285, 279, 263, 250, 221, 206, 180, 168, 138, 110. Anal. Calcd for (1H, dd, H-7), 6.86 (1H, t, H-9), 6.97 (1H, bs, N6–H), 7.27 (1H, dt, H-8),
C28H37N3O: C, 77.91; H, 8.64; N, 9.74. Found: C, 77.72; H, 8.98; N, 9.85.
cis-1ꢀ-Benzyl-1-(4-tert-butylcyclohexyl)-spiro[piperidine-4,2ꢀ(1ꢀH)-
7.65 (1H, dd, H-10), 8.05 (1H, s, H-2). MS m/z: 172 (Mꢇ), 145. Anal. Calcd
for C9H8N4: C, 62.78; H, 4.68; N, 32.54. Found: C, 62.93; H, 4.43; N, 32.25.
NOP Receptor Binding Assay in Membrane Preparations Enriched
quinazolin]-4ꢀ(3ꢀH)-one (3t cis) Compound 3t cis was obtained from
1
2e cis in 21% yield, white solids from ethyl acetate, mp 200—202 °C. H- plasma membranes from transfected cells were prepared by differential cen-
NMR (DMSO-d6) d: 0.77 (9H, s, tert-butyl), 1.01 (1H, m, H-4ꢈ), 1.27 (6H, trifugations37) and stored at ꢆ80 °C (protein concentration 2—4 mg/ml) until
m, H-2ꢈax, H-6ꢈax, H-3ꢈ, H-5ꢈ), 1.86 (6H, m, H-2ax, H-6ax, H-3ax, H-5ax, H-
2ꢈeq, H-6ꢈeq) 2.20 (2H, d, H-3eq, H-5eq, Jgemꢁ10.2 Hz), 2.29 (1H, t, H-1ꢈeq,
Jꢁ6.4 Hz), 2.76 (2H, d, H-2eq, H-6eq, Jgemꢁ11.7 Hz), 4.59 (2H, s, 1ꢀ-benzyl
CH2) 6.69 (1H, t, H-8ꢀ, Jorthoꢁ8.4 Hz), 6.76 (1H, t, H-6ꢀ, Jorthoꢁ7.4 Hz), 7.27
used. The binding of 125I-Tyr14-nociceptin (Perkin Elmer Life Sciences) was
measured in 1 ml reaction mixture containing 50 mM Hepes–Tris pH 7.4,
10 mM MgSO4, 10 mM leupeptin, 10 mM bestatin, 0.1 mg/ml bacitracin, 0.1%
(w/v) bovine serum albumin (BSA), and 3 mg of membrane proteins from
(6H, m, overlapped benzyl group aromatics and H-7ꢀ), 7.71 (1H, d, H-5ꢀ, HEK-293 cells transfected with the NOP receptor as previously described.26)
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orthoꢁ7.6 Hz), 8.03 (1H, s, NH). MS m/z: 445 (Mꢇ), 354, 326, 307, 299, The concentration of radiotracer was maintained constant at 50000—
263, 250, 235, 220, 182, 161, 132, 91. Anal. Calcd for C29H39N3O: C, 78.16; 100000 cpm in the presence of increasing concentrations of compounds to
H, 8.82; N, 9.43. Found: C, 78.03; H, 8.53; N, 9.71. be tested. Reactions lasted 90 min at room temperature and were terminated
trans-1ꢀ-Benzyl-1-(4-tert-butylcyclohexyl)-spiro[piperidine-4,2ꢀ(1ꢀH)- by rapid filtration onto GF/B glass fiber filtering microplates pretreated with
quinazolin]-4ꢀ(3ꢀH)-one (3t trans) Compound 3t trans was obtained from 0.1% Ethylene Imine Polymer (PEI) (Filtermate 196; Packard Instruments,
2e trans in 21% yield, white solids from ethyl acetate, mp 254—256 °C. 1H-
Meriden, CT). Filters were washed three times with 1 ml of ice-cold 50 mM

622
Vol. 54, No. 5
Tris–HCl pH 7.4 and allowed to dry for 30 min at 37 °C. The plates were
counted in a Top Count (Packard Instruments) after the addition (50 ml) of
Microscint 20 (Packard) to each well.
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(1999).
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IC50 values were obtained by fitting the competition curves according to a
4-parameter logistic model (ALLFIT program).38)
d, k, m Receptors Binding Assay The binding affinities for human d, k
and m receptors were determined with [3H]-naltrindole for d receptor and 12) Calò G., Guerrini R., Rizzi A., Salvadori S., Regoli D., British J. Phar-
with [3H]-diprenorphine for k and m receptors.39,40)
macol., 129, 1261—1283 (2000).
A suspension of membranes (5—15 mg) of HEK-293 cells expressing d 13) Zaveri N. T., Life Sci., 73, 663—678 (2003).
receptors26) and k receptors (Perkin Elmer Life Sciences) and of CHO cells 14) Wichmann J., Adam G., Röver S., Hennig M., Scalone M., Cesura A.
expressing m receptors (Perkin Elmer Life Sciences) was incubated with the
radioligand (30000—50000 cpm) at room temperature for 2 h in a total vol-
ume of 1 ml containing 50 mM Hepes–Tris pH 7.4, 100 mM NaCl, 0.1 mg/ml
bacitracin, 0.1% (w/v) BSA and increasing concentrations of compounds to
M., Dautzenberg F. M., Jenck F., Eur. J. Med. Chem., 35, 839—851
(2000).
15) Satoh A., Kawamoto H., Ozaki S., Ito Y., Iwasawa Y., Patent WO
00/34280 (2000) [Chem. Abstr., 133, 17466u (2000)].
be tested. Samples were incubated for 90 min at room temperature, filtered 16) Rover S., Wichmann J., Jenck F., Adam G., Cesura A. M., Bioorg.
onto GF/B glass fiber filtering microplates (Filtermate 196; Packard Instru- Med. Chem. Lett., 10, 831—834 (2000).
ments, Meriden, CT, U.S.A.) and washed three times with 1 ml of ice cold 17) Bignan G. C., Battista K., Connolly P. J., Orsini M. J., Liu J., Middle-
50 mM Tris–HCl pH 7.4 prior to scintillation counting on a Packard Top
Count.
ton S. A., Reitz A. B., Bioorg. Med. Chem. Lett., 15, 5022—5026
(2005).
IC50 values were obtained by fitting the competition curves according to a 18) Topham C. M., Mouledous L., Poda G., Maigret B., Meunier J. C.,
4-parameter logistic model (ALLFIT program).38)
Protein Eng., 11, 1163—1179 (1998).
19) Huang X. Q., Jiang H. L., Luo X. M., Chen K. X., Zhu Y. C., Ji R. Y.,
Cao Y., Acta Pharmacol. Sin., 21, 529—535 (2000).
GTPgS Binding The 35S GTPgS binding was determined in a 1 ml re-
action mixture containing 50 mM Hepes–Tris pH 7.4, 1 mM dithiothreitol
(DTT), 100 mM NaCl, 10 mM MgSO4, 0.1 nM 35S GTPgS (Perkin Elmer Life 20) Meunier J. C., Mouledous L., Topham C. M., Peptides, 21, 893—900
Sciences), 300 nM GDP (or concentrations varying between 0.1 nM and
100 mM) and 1—2 mg of membrane proteins, with or without compounds to
be tested.26) The dose–response curves of nociceptin were determined in ab-
sence and in presence of fixed concentrations of the tested compounds (0.1,
1, 100 mM).41) Samples were incubated for 90 min at room temperature, fil-
(2000).
21) Huang X. Q., Jiang H. L., Luo X. M., Chen K. X., Zhu Y. C., Ji R. Y.,
Cao Y., Acta Pharmacol. Sin., 21, 536—546 (2000).
22) Bröer B. M., Gurrath M., Höltje H. D., J. Comput. Aid. Mol. Des., 17,
739—754 (2003).
tered onto GF/B glass fiber filtering microplates (Filtermate 196; Packard 23) Tschaen D. M., Abramson L., Cai D., Desmond R., Dolling U. H.,
Instruments, Meriden, CT. U.S.A.) and washed three times with 1 ml of ice
cold 50 mM Tris–HCl pH 7.4 prior to scintillation counting on a Packard Top
Count. Non specific binding was determined in the presence of 10 mM
GTPgS.
Frey L., Karady S., Shi Y. J., Verhoeven T. R., J. Org. Chem., 60,
4324—4330 (1995).
24) Ramalingam K., Balasubramanian M., Baliah V., Indian J. Chem., 10,
366—369 (1972).
The data of dose–response experiments were analyzed using program 25) Potts K. T., Brugel E. G., J. Org. Chem., 35, 3448—3451 (1970).
ALLFIT, to compute the EC50 in the absence and presence of the various 26) Molinari P., Ambrosio C., Riitano D., Sbraccia M., Grò M. C., Costa
concentrations of antagonist.38)
T., J. Biol. Chem., 278, 15778—15788 (2003).
27) Zaveri N., Jiang F., Olsen C., Polgar W., Toll L., AAPS J., 7, E345—
E352 (2005) (http://www.aapsj.org).
Aknowlegments We wish to thank Dr. Luciana Turchetto for mass
spectra, Mr. Antonino Puccio and Mr. Leo Zanitti for technical assistance. 28) Arunlakshana O., Schild H. O., Br. J. Pharmacol., 14, 48—58 (1959).
Moreover we express our thanks to Prof. H. D. Höltje and to Prof. H. Jiang 29) Stuart J. P. P., J. Comput. Aided Mol. Design, 4, 1—105 (1990).
and Prof. X. Luo for kindly providing the NOP receptor 3D models.
30) Mouledous L., Topham C. M., Moisand C., Mollereau C., Meunier J.
C., Mol. Pharmacol., 57, 495—502 (2000).
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